I've been playing one a bit lately. Not one of the big, mainstream ones either. A turn based strategy type thing called Space Empires V (game company webpage here
- you'll need to click the link for the game). It's rather good... along similar lines to the Civilization games, but interstellar rather than international. It's also not shy on scope or variation in how you can progress things.( Game talk )
If anyone else likes this kind of game and picks it up, let me know at some point. I suspect that a networked game might be interesting, if somewhat slow at times due to waiting for each other to complete their turns. I'd suggest he simultaneous turns approach, but even then there could be delays.