Found this on another forum I'm a member of. It's a free top-down (?) tactical shooter that you can get through Steam. You and three others run around a set of missions trying to accomplish a set of goals without getting eaten by swarms of aliens. I havent had a chance to play past the offline practice mission yet (that and the idea of narcisstic little 14yo's whining through their headsets isn't all that appealing), but it seems fairly sweet. Very atmospheric as well. If anyone wants to play it online, my steam username is Charonte (ironically). I don't use Steam all that often so you're better off posting here or something. Will be doing prep work and spray painting for the next 8ish hours, but after that I'm free all weekend and plan on being awake and plastered for most of it. Come to think of it, there should actually be a House of Lords steam group or something. http://www.alienswarm.com/index.html
Don't worry, no one uses voice in Alien Swarm. It's also very good, but it is community content-oriented, and only comes with a single (2 hours-ish) campaign. It's quite entertaining though.