I own...

Tetris DS -- I'm addicted to multiplayer.
New Super Mario Brothers -- It was fun, but incredibly easy. It only kept my occupied for a day and a half before I beat it. I played the minigames more than the actual game.
Secret of Mana -- I haven't even played it.
Sonic Rush -- <3 It's so fast.
Mario 64 DS -- The controls are funky, but it's appreciated nostalgia with my lack of a N64.
Mario Kart DS -- Also addicted to multiplayer.
Harvest Moon DS -- I like the GBA version a lot better. I stopped playing as soon as I realized all the girls are stupid.

I've been hunting for Hotel Dusk: Room 215 since it came out, but I haven't been able to find the stupid thing ANYWHERE. Best Buy said the item was discontinued, but I'm hoping the guy was just a moron and doesn't know what he's talking about. They were my last hope, aside from eBay.

Also, new Pokémon in three days!!