Another gaming site that has a large community of over 84,000 members, who created and uploaded over 36,000 games. Games they made with gamemaker software. The most recent one is Gamemaker 7 which uses drag-and-drop actions letting just about anyone create professional looking games. YoYogames.com is very polished and is very much similar to YouTube. Where every game that's uploaded has it's own page with reviews, comments, info,sharing,tags and even embeding codes.
I did get play around with gamemaker 7 some time ago. But here is the game that I had made and uploaded.
Sandbox is free and open source 3D game maker. Features of sandbox include kid friendly,(you find any in game killing here), editing is done within the game itself. Can be edited cooperatively over the web, has different games modes. Which include cart,sidescroller,movie and RPG. It also comes with several custom pre-made maps that any one can use and create their own game with. Just to name a few of the many features.
This software has also gained a lot recognition and awards. This year alone it won the Total PC Gaming mag award for February, the PCFormat Mag award for February, and voted one of the top 100 projects of 08 at moddb.com.
Additionally Sandbox can used on Windows or Mac. And you can find out more about Sandbox on their site. As well as a forum and wiki to learn more about this great software