The DS import game I was talking about is called Yosumin. You can play a free version of it here:
It has great music, and is horribly addicting. The premise of the game is to clear out shapes by clicking on the corners of squares/rectangles that have the same shape. Here's an example:
In this picture, clicking on the blue squares highlighted or the yellow diamonds in the drawn square will "clear" those blocks.
The free version now has ads that weren't there before Square-Enix licensed it, and you may not be able to play past the first couple of stages, which is disappointing, because it gets even crazier later on when new shapes get added.