Fond of rumpots, crackpots, and how are you, Mr. Wilson?

Disc Drivin' -- it's free (ad-supported) or a few bucks if you don't want ads. It's basically Pitchcar. And you can play online (asynchronously), so you can play against me and ckd. The iPhone version of Carcassonne is also awesome (and allows online play) but is $10.

Angry Birds has both free and paid versions. I think the pay versions are still worth the money, but grabbing the free one first to try the game just makes sense.

If you like action games, Gun Bros is surprisingly addictive (and free).

Frotz is a free Interactive Fiction app.

The free DominionKD app is the one CKD uses to select cards for playing Dominion.

For non-game stuff, there are the obvious ereaders (Kindle, iBooks, etc), the Adult Swim and ABC Player apps for free TV shows, and there are a dozen or so competing note-taking apps.