I got one for Christmas and I need to stock up my library; thus far I only have one game, but it does kick ass. So I'll start the list with it: - Geometry Wars: Galaxies. It puts the steroids in Asteroids; it's the exact same kind of game, but with much more color and variation. Great fun. - - - EDIT: I did some research on Gamespot and bought some more games. Thus far they're all good too: - Yoshi's Island DS. It's your typical Mario-style platformer, but Yoshi isn't quite so whored-out as Mario, so it's still fun to try to figure out how to use his moves. - Advance Wars: Days of Ruin. The best (only?) strategy game for the DS, wrapped in a new post-meteor-apocalypse skin. Now features internet play, if you can figure out how to get the WiFi to work. - Kirby: Canvas Curse. This one was hard to find because it's old, but damn what a great game! The premise is Kirby gets turned into a ball and you have to guide him by drawing chutes and ramps and walls to get him to roll where you want. I had my doubts about how good a stylus-only control scheme could be, especially considering the game has to interpret what you draw on the screen, but it actually works great -- as good as my imagination could come up with. - - - Next on the list is Metroid Prime: Hunters, I think, and there's a racing game in the works with a build-your-own-track feature -- if they implement that one well, it should be a safe bet too. Ah, who needs money anyway.