http://www.frozensynapse.com/
Awesome simultaneous turn-based strategy and tactics. Overall a great game, quite good at blowing extra minutes between events and things. Sit down, take a turn, and move on. If the other player is online, it's also good for wasting hours of time in a single go, if that's more your speed.
IGN is Olothontor. I'm on the Texas3 server.