Love the Magnetic Needles, Micro Spirograph, Pop Balloons, LavaLamp: they are very cool.<p>Visual sort is also impressive.<p>It reminds me all those little programs I used to do in my 10-18 yo days. (I was programming mostly on a Mac with Hypercard, Think Pascal, Resedit back then).<p>I used to reproduce all the small games I could program (Snake, Tetris, Solitary, Pacman, Breakout...) plus some educational projects (vocabulary quizz, irregular verbs, math plot, fractal drawing)