Physion
http://physion.net/
A 2D Physics program that lets you build and experiment with mechanisms having realistic physical properties. Objects can be connected with joints, springs, pulleys etc. There are demonstration videos to help you get started. Free download.

Kodu
http://www.kodugamelab.com/
Free download that lets you create games on the PC and XBox via a simple visual programming language. Kodu can be used to teach creativity, problem solving, storytelling, as well as programming. Lots of supporting videos and documentation.

My Doodle Game
http://mydoodlegame.com/
My Doodle Game is a fun and creative game-making tool, where you can literally draw your own games and then play them! The application comes with some pre-made characters and games. You can use these or just draw your own and build up a personal library.
Free PC download and also available as an Ipad app.
 

Minetest
http://minetest.net
Minetest is an infinite-world block sandbox game and game-engine, inspired by Minecraft. Walk around, dig and build in an infinite voxel world, and craft stuff from raw materials to help you along the way. Multiplayer support via servers hosted by users. Runs on Windows, Linux and OS X.

GameMaker
http://www.yoyogames.com/gamemaker
Game Maker allows you to make computer games, using easy to learn drag-and-drop actions. You can make games with backgrounds, animated graphics, music and sound effects, and even 3D games! And when you've become more experienced, there is a built-in programming language. Tutorials on getting started are available on the website.

WolfQuest
http://www.wolfquest.org/
An immersive, 3D wildlife simulation game, WolfQuest challenges players to learn about wolf ecology by living the life of a wild wolf in Yellowstone National Park. Players play alone or with up to four friends in on-line multiplayer games. Free download.
 

Pivot Stickfigure Animator 
http://www.softwaregeek.com/download/pivot_stickfigure_animator.html
Pivot Stickfigure Animator is a unique software, that allows you to create stick figure animations easily and without any artistic skills. You can move the sections of the sick figure and easily create a chain of animation frames that can be previewed as you go. You can use more than one stick-figure in the animation, and even create your own stick figures using an easy to use visual editor that lets you assemble objects out of lines and circles. You can optionally set animation size, speed and more. The result can be saved as an animated GIF file. Fun and easy to use, surprisingly well featured. Example here
Stykz is an alternative animation program (very similar to Pivot) available free for Windows, Mac and Linux computers.

Artrage 
http://www.ambientdesign.com/artrage.html
ArtRage is a painting package designed to provide a realistic and fun simulation of using paint on a canvas, along with pens, pencils, crayons, and other tools. You can run ArtRage on a normal Windows machine with a mouse, but it works particularly well if you have a graphics tablet. ArtRage is all about playing with paint without the mess, and having fun in the process. You can paint your own image from a blank canvas to completed work, or load in a picture to trace and have the tools pick their colours for you as you paint over it. The starter edition can be downloaded free of charge. Examples here.

Simon Tatham's Portable Puzzle Collection
http://www.chiark.greenend.org.uk/~sgtatham/puzzles/
27 different abstract puzzles that you can run on Windows, Mac and Linux computers. Neat re-packaging of some well-known (and some not so well known) puzzles in a portable format. You can download single puzzles or the whole collection. 'Rectangles' is great for getting children to think about the different ways of factoring numbers.

Food Force
http://www.food-force.com

Tangrams 
tangram.zip
This freeware is downloadable here. You will need to unzip the file and run Setup.exe
Tangram is a well known Chinese puzzle. The goal is to form various shapes from 7 pieces. This program challenges you to solve a large number of these puzzles. Puzzles range from very simple ones for small children to difficult ones for adults. An editor is provided that allows you create your own collections of puzzles. You can even use different sets of pieces. The program is very easy to use and help is provided within the program.
An updated (but no longer free) version of this software is available with 2 other programs as 'Professor Roberts' ICT Problem Solving Kit'.

Crocodile Clips elementary 
http://www.crocodile-clips.com/s3_4.htm
Crocodile Clips Elementary is a free download that helps teach the first principles of electricity (Windows and Macintosh) It has an easy-to-use interface and only the components you need at elementary level.
Crocodile Clips Elementary comes with a set of worksheets introducing electric current and circuits, and you can also use the pictorial components to build your own circuits, adding text and images as you go. All of the circuits you design simulate just like in real life, letting you experiment with electricity in a safe and enjoyable way.
Also worth downloading is the demo of Crocodile ICT  - a tool for studying programming and control (nominally for 10-18 year-olds).

Drumsteps
http://www.cs.tcd.ie/crite/projects/creative-music/drumsteps/
Ready to try something a bit more complicated than Beetmaker? You will need to work your way through the tutorials to get to grips with this software, but it's well worth the effort.
Drumsteps is a dynamic graphical interface which enables children to create, manipulate, edit and save original pieces of percussion music. Users create sets of steps, ladders, trapdoors and other graphical elements and cause balls to drop through their constructions producing musical sounds. Each graphical element is carefully chosen so as to have an equivalent musical meaning allowing fully intuitive musical expression.
If you have trouble getting the program to run check the instructions here

Envisioneer Express
http://www.envisioneerexpress.com/
Easy to use house design program. Create floorplans, add doors, windows, stairs and furniture, then move through your house in 3D. Useable by children 7+.
You need to provide your name details to download this free software. Print-outs are watermarked 'not for commercial use', otherwise all functions of the program are enabled.

Moving Sketch
http://www-ui.is.s.u-tokyo.ac.jp/~takeo/research/rigid/movingsketch/
Make your drawings move! Wonderfully simple to operate - once you know how; you will need to watch the video demos to understand how to operate the program.
Has a few bugs - but is well worth playing with.

NASA World Wind
http://worldwind.arc.nasa.gov/
lets you zoom from satellite altitude into any place on Earth. Leveraging Landsat satellite imagery and Shuttle Radar Topography Mission data, World Wind lets you experience Earth terrain in visually rich 3D. You'll need a fast Internet connection and it's a big download to get the program - but it's entirely free and the detail on American cities is amazing. See the level of detail available for the UK here

Also try Flash Earth to access aerial views without installing any software. N.B. choosing 'Microsoft VE' will give best results for most UK areas.

Tower of Babel (XP or 98+Net)
site not available at present  - download from our site here
The goal of the game is to build the tower which will survive some period of time. The height of the tower after this period is the final score. Every tower must be placed in edit environment - open it first. You will see that some points are surrounded by circles. Those are constant points - you can attach your construction to them. You can use various materials (available via popup menu) - steel, wood, steel rope and even bungee. Every material has different properties - mass, max length and hardiness. When the tower is ready - simulate it - the final height achieved will be displayed after simulation time elapses. You can upload your tower to see if you are the best engineer around.

Instructions
1. Open edit environment (Menu File\Open Edit Environment)
2. Select tool (right click anywhere in the program window).
3. Left click anywhere to start building. You should see little circle surrounding the start point.
4. Left click anywhere in the highlighted area to place first connector.
5. Build other connectors the same way. Remember -attach your construction to one or more constant points or your tower will    
    fall!
6. When your tower is ready simulate it (Menu Simulate\one of the speeds)
7. In upper left corner you can see actual height of the tower and simulation time left. Remember that what counts is the height of the tower at the moment the simulation time elapses.

Arcimboldo Art Producer
http://www.middlestreet.org/Arch.htm - online version.
Download self-contained file here
Arcimboldo painted many pictures building faces from fruit and vegetables (and sometimes creatures, books and other objects. Create a portrait using just fruit and vegetables (and a few other odds and ends).  Click the help button to see how to use the program.

The META Learning Game
http://www.gamelearning.pwp.blueyonder.co.uk/clubs/resources/resources.htm
An interactive 3D game for promoting discussion about the history of learning.
Includes four short gaming environments: a prehistoric caveman learning by trial and error; apprenticeship in a medieval blacksmith's workshop; rote learning in a Victorian classroom and a vision of learning in the future. Download is at the bottom of the linked page.
    Use the arrow keys to move around and space/enter to interact with objects.
    Holding tab takes you forward to the next screen or scenario.
    Holding backspace takes you back to the previous screen or scenario.
    Escape quits the program.

Storytelling Alice
http://www.alice.org/kelleher/storytelling
Storytelling Alice is a modified version of the Alice program, which includes a story-based tutorial, a wider range of pre-defined characters and a selection of higher-level interactions already programmed in. This makes the program easier to use for primary-age pupils interested in programming and creating 3D worlds. Make sure you also download the 'Storytelling Alice Brochure' to help you get started.

Scratch
http://scratch.mit.edu/
Scratch is a new free programming language that lets you create your own interactive
stories, games, music, and art.
See also Build Your Own Blocks - an advanced version of Scratch.
See a video of this programme on the BBC site here
MIT App Inventor uses a Scratch-like system to let you program Apps for your Android phone or tablet.

KidsRuby
http://kidsruby.com/

Sudoku
http://www.easton.me.uk/sudoku/online.php
Sudoku is a puzzle game that became very popular in various newspapers during 2005. It is a game of logic rather than arithmetic.
To solve a Su Doku puzzle, every digit from 1 to 9 must appear in each of the nine vertical columns, in each of the nine horizontal rows, and in each of the nine boxes. They range in difficulty from easy to very hard, depending on the positioning of the numbers you are given to start with.
The link takes you to a site where you can download a free version of a program that generates puzzles of 3 different levels of difficulty.

Bricks
http://www.bricks-game.de/indexuk.html
Bricks is an ingenious puzzle-game involving sliding blocks to allow bricks to reach certain positions, providing a challenge for your logic and sequencing skills. There are a wide variety of levels to download, including a 'Junior' level.
 

RobotProg
http://www.physicsbox.com/indexrobotprogen.html
Program a virtual robot using a flowchart. Draw a flowchart, run the program and watch the robot execute your instructions. With RobotProg you can learn the basics of programming  by working your way through graded levels.
In the final level, you can program several robots to play games in the same arena.
To help get started download or view the tutorial at www.physicsbox.com/supportrobotprogen.html
 

Robomind 2.0
http://www.robomind.net/en/index.html
RoboMind is a first introduction to automation and programming without any prerequired knowledge. The example exercises come in varying degrees of difficulty -some of them are simple and can be solved relatively quickly, while others require studying the program documentation and considerable thought. Primary-age pupils can get acquainted with writing commands to navigate the robot through its environment, while older users can get to grips with programming structures and automation theory.
Robomind is free for individual use.

Colobot - demo
http://www.ceebot.com/colobot/game-e.php
Colobot combines both a real time game of strategy and an initiation to programming. You are at the head of a space expedition and you are assisted only by some robots. Your mission consists in successive attempts at the exploration and colonization of various planets.
Great fun as an introduction to programming. Epsitec also have some other interesting games here

Bridge Construction Set - demo
http://www.chroniclogic.com
In Bridge Construction Set you design and build bridges and then stress-test them to see how your creations hold up under pressure. When test vehicles pass over your bridge and make it safely across you know you've succeeded. If they plummet into the river you know you need to go back to the drawing board.
 

Scally's World of Problems - demo
http://www.topologika.co.uk/catalogue/scallyprob.htm
Scally's World of Problems encourages a co-operative approach to problem-solving, and when pupils have familiarised themselves with the roles of all the maze icons, they can be further stretched to create their own puzzles for others to tackle. This takes the activity and the learning beyond problem-solving into the creative process, drawing on imagination and planning skills.
 

Return of the Incredible Machine - Contraptions - demo
http://uk.gamespot.com/pc/puzzle/returnoftheimc/downloads.html
Most recent of the 'Incredible Machine' series. Contraptions is an apt title as you will be tinkering with various contraptions, or building your own, as you strive to complete your task. Sometimes there is more than one solution to a particular problem, and you can play around setting the parts in place without stress as there is no time limit. Once your contraption is ready you just click on the 'start' button to see your handiwork and strategy unfold, or fall in a heap as the case may be.
The 'Incredible Machine' programs seem to be hard to obtain currently, but are worth watching out for as they are all-time classics for children who love problem-solving.

Crazy Machines - New Challenges - demo
http://games.softpedia.com/get/Games-Demo/Crazy-Machines-II.shtml
Similar idea to the 'Incredible Machine' series, with updated graphics.
Has been available in 3 versions - 'Crazy Machines', 'Crazy Machines 2' and 'Crazy Machines - New Challenges'. The link takes you to a downloadable demo of 'New Challenges'.
The original game is available on Amazon here

Professor Fizzwizzle - demo
http://www.bigfishgames.com/downloads/professorfizzwizzl/
Professor Fizzwizzle is a puzzle game, in which it's your job to help the diminutive prof to use his brains and his gadgets to solve each of 230 exciting levels. As you solve levels, photos in the prof's gallery are unlocked that'll reveal him and his friends all over the world!
A wide variety of difficulty levels, with no time limits and your progress saved as you go. Even make your own creations with the in-game level editor!
 

Toblo
https://www.digipen.edu/?id=1170&proj=465
Toblo is a fast paced capture the flag game that takes place in a fully destructible block world. Pick one of two teams: angels or demons. Play against intelligent AI bots or against up to 4 friends over a Local Area Network. Interesting collaborative game to play over your school network! Free download.

Real Lives - demo
http://www.educationalsimulations.com/
Real Lives is a unique, interactive life sim that enables you to live one of billions of lives in any country in the world. Through statistically accurate events, Real Lives brings to life different cultures, political systems, economic opportunities, personal decisions, health issues, family issues, schooling, jobs, religions, geography, war, peace, and more!
The  level of language involved and the interpretation of data involved makes this simulation mainly suitable for older children, but also for very able children 8+ , though they may need some encouragement initially to get over the lack of graphics and become 'involved' with their character. This program is like a realistic version of games like the Japanese PrincessMaker with the same fascination of watching the life-story of your character unfold. Real Lives is now available in the UK from AVP

MicroWorlds Jr - demo
http://www.microworlds.com/solutions/mwjunior.html
Easy to learn and use with simple, point & click operation, using child-friendly symbols and comprehensive audio help. MicroWorlds JR develops: creativity, problem solving, critical thinking skills and logic.  
MicroWorlds JR encourages children to:
   Explore mathematical and other ideas such as number, geometry, patterns & movement.
   Use iconic commands and the turtle to create any type of project they can imagine.
   Use the computer as a creativity and thinking tool.
Although the programming is done entirely through use of symbols (making the program suitable for all ages - no reading necessary!) this in no way prevents the creation of  interestingly complex projects. The all-time favourite version of Logo for Primary-age children. N.B. demo does not allow printing or saving and times out after 30 days.