Electroplankton is a good one. Arrange plankton to make music, and you can get surprisingly intricate. Also, best use of the Mic on the DS.
Another strange game is A Tale in the Desert. In a way, its overly normal, but I think you can call it weird because its so incredibly normal, yet it is a game and STILL FUN. No special powers, no combat, no advanced graphics, you make a character, and go bang rocks together, grow and plant grass, gather sand, mud and clay...at least in the sims theres some amusing wackiness. And yet, there is a real sense of achievement, and it has the single most polite, coherent player chat out of any game ever. I once walked home in a thunderstorm on my lunch hour so I could dry bricks. No joke.