Bridge

Bridge is a card game that uses a combination of skills including tactics, probability, communication, and teamwork. Once you've played it, other games in its family such as spades, hearts, and Wizard start to seem pretty dull. And while it's a serious game, it is also a good social activity; you play in pairs, and there is a just enough randomness to keep everything spiced up.

There is a newsgroup git.talk.bridge where you can go to talk about bridge or set up groups at other times.

You can also play online. I play a lot on Floater, because it's free and open source and runs on everything.