I made a program to help me understand a math problem better, and I found it rather fun to play with--something to share with other people. To use it, click in the white area and see what happens. You can reset it by clicking in the black area.
I see at least two games you can play with it:
See how few clicks are needed to color all the white squares.
Make one click, then click only on green squares. See if you can color all the squares that way.
Perhaps you can find other things to do. I think it's a nice toy to use when your mind's fried from a hard day's work.