Aaaaaarrrrggghhhh. I'm hooked on "Set" (via Boing Boing).
I don't usually play any computer games, but once in a blue moon I get hooked on something.
This is a card game where you have to identify sets of 3 cards from a group of 12.
Sounds easy. It completely does your brain in trying to find the Set.
You can play it with dealt cards, or there are some online versions to play with yourself.
I warn you, it's very very addictive.
Set Game Online.