In case some of you have not noticed, I really like the game Quantz. It's quite simply a very enjoyable experience. It is visually stimulating, it has excellent, smooth gameplay, and it's unique and simple enough that I don't have to lose myself in the game to enjoy it.
Quantz is not only a really cool game, it's also one of the few high-class commercial games written for Linux, Mac, and Windows. From talking with some of the developers, you'd also learn that it is written in Scheme, too! I mean, does it get any better?