Scratch that game-maker itch
Scratch from MIT : http://scratch.mit.edu is a graphical interface for creating logical object-oriented programs, quickly and easily. I read a review of it in MAKE Magazine some months ago and finally tried it out. Looks extremely promising, and its easy to put together a simple intelligent animation in minutes. (well, a bit more for reading the instructions - but after I read them it didn't take long)
Although the interface allows drag and drop - avoiding any syntax errors - the chunks are all code. So its real programming, but with an interface that eliminates possibility for error and helps kids achieve step by step success.
Runs on Windows XP or higher, Ubuntu Linux or MacOS 10.4+.