Any good odd-number-player PC games?

A group of friends and I jump online to play PC games together every Tuesday night, usually numbering anywhere between 6 - 10 people. However, this leads us to many instances where we have an odd number of people (seven tends to be the magic number). While we don't really have any qualms about joining populated servers, we tend to best enjoy games where we can all just game together without having to worry about random players screwing up the dynamics of our group games. 
 
Are there any good PC games that anyone could recommend that work well for odd-numbered groups of players? Games with free-for-all modes work well right now, but that usually leads to us being locked into the FPS or RTS genres, and we're maybe hoping to find something unique to play. However, I'll gladly accept FPS and RTS recommendations.

Not sure what else you would play with that many people. Turn based Strategy would get real old real fast.
 
I'm gonna go ahead and recommend any iteration of the Unreal Tournament series.

Cat Planet

Unreal Tournament 2004 or Quake 3 would be my picks, just stick to non-team based modes when you have odd numbers of people.

I would suggest UT over Quake 3 to start off with just for the shear number of gametypes available out of the box.

Left 4 Dead one versus matches are really good for situations like that

We've also tried out Altitude and sometimes we play CS:S with bots.

Try giving The Ship a go. I can see that game being a lot more fun if you're playing with people locally. Sadly, there's no demo.
 
 http://store.steampowered.com/sub/333/

Would definitely like more suggestions.

 Killing Floor is for up to 6 people which is very good if you've only got that many. Obviously, 7 is too many for that. 
Left 4 Dead 1 has versus mode which is for 8 people. It's good with 7 though as the infected side doesn't NEED to be full to have a successful game. 
Someone else said The Ship. I second that. 
Racing games like DiRT 2. I think DiRT 2 can have a fair few people. 
GTAIV has fun multiplayer. 
 
 and then there is also mods. 
 
Firearms: Source 
Orion 
Fistful of Frags 
Resistance and Liberation  
Human Error Co-op 
 
Just to name a few.

Diablo 2 is always a great group game and holds up well after all these years. A group your size gives you lots of different options as well.