This is a really fun online card game I was linked to recently.
Basically it's like Apples to Apples, if you've ever played that, you're given a hand of white cards with words/phrases on them, and a black card is played each round. The objective is to pick a white card which you feel fits in the blank on the black card.
It's a ton of fun, especially if you have people to shoot the shit with in vent/skype or something.

Here's a screenshot I just took of the UI:


And here's the link: http://cah.socialgamer.net/game.jsp


Note: it's still in development, so there are some issues such as no timeout for afks.