I'm really digging the Nintendo DS thing - especially this new game I got for my birthday last week called Clubhouse Games. It's a pretty cheap buy, but comes loaded with about 40 classic board, bar, and card games. It also seems like they've got all the bases covered with 1-cart local multiplayer; WiFi internet multiplayer; and in-game pictochat. There's also a decent amount of incentive to explore all the games to unlock even more games, as well as little gimmes like background music styles and game background graphics. I'd say this is a must have to keep with you at all times in your DS case. Just bust it out in any DS-equipped group and pwn n00bs in a game of Grid Battle (nee Battleship™), Last Card Plus (nee Uno™), Turncoat (nee Othello™), or even bowling or darts.
Oh, and for anyone who happens to want to play me, here's my WiFi friend code for Clubhouse Games:
5283 6308 0677
Let me know if you add me, drop your code here, and maybe hit me with an IM to play.