gamemaker!

If you want to make your own games, this is the program to try first. Game Maker installs quickly and launches automatically, starting up by generating a new project. A basic project includes sprites, sounds, background, paths, scripts, data files, time lines, objects, and room features, as well as game information and options, all of which you can configure freely. In particular, the application offers a good deal of control over sprites, which can be scaled, rotated, made partially transparent, and blended with a color. Each feature offers samples to show you how to create your masterpiece. All you need is imagination and the freeware's help file. You might not be able to create something, such as Doom or Heroes of Might and Magic, but mah-jongg and golf are doable. Though writing a game might seem intimidating, Game Maker brings it within reach.

Useful links:
http://www.yoyogames.com/

Kerpoof

Kerpoof's goal is to become a leading destination site for children through a suite of activities that are enriching as well as entertaining. While mindless fun has its place, creating a place for mindful fun is the mission of Kerpoof. On Kerpoof, users can create art, stories, and animated movies using a simple 3D interface. When users are done, they can save it to their gallery, share it with others, and vote on their favorites.

Useful links:
http://www.kerpoof.com/