I can not enthuse enough about this programme. I'm NOT a computer programmer by any stretch of the imagination but both myself and my son have enjoyed working together, and learning together, with this software. It really is the lego of computing, you just drag the programming "blocks" together, if you use the wrong one you just drag it off and replace it with another.

You can use this to build simple games or short cartoons.
Scratch is completely FREE and is being developed at MIT Visit the Scratch site and you will be able to see hundreds of other examples of games and
presentations people have made. You can also download the programme and see plenty of help (forum and help docs). Even better, once you have installed the programme, you can download the "code" for any of the games you see on there so you can see how other people made their games, alter them and/ or improve them for yourself.