I'm going to put in my vote for trying out League Of Legends. It's a bit of a change for folks, and even though it appears to be RTS, it's not. It's a lot like Defense of the Ancients (which we played at the LAN party), but we can play against AI depending on how many people show up.

It's also free to play, so the only thing you'll be out is the time it takes to download it. The way they do the free thing is that of the 40 or so champions, only about 10 are available for free at any given time. You can permanently unlock champions to use by spending money, or be spending points you get for playing. To give you an idea, if you play about six or so games total, you'll pretty much definitely have enough to buy a tier 1 champion.

Check it out at www.leagueoflegends.com. You can also go to www.leaguecraft.com to find some guides for the various champions you can play. I'll try and find a post that says which champions are available this week, but I think they usually change it on Wednesday or something anyways, so it might change.

Let me know what you guys think.