Last night, Matt(aka Sunder) mentioned Team Fortress 2 went free to play. At first I thought he was crazy but I confirmed he was correct. For those that like first person shooters with team based class play, this is a fun game to try. I can say I've wasted a bit of time playing it and it has a certain comedic quality to it thanks to the way they presented the characters/classes in it.
You will need to download the steam client but the supplied link up above will assist you in doing so as well as getting a steam account setup. It's all free so don't worry about having to spend any money. Steam is a nice little program which sells a lot of games in a digital format rather than needing a CD/DVD to install and play them. If you do pickup Team Fortress 2, post about it here or join our group on steam as detailed in this forum! That way we can see when each other are online and maybe get into a game as a group.
For more information on Team Fortress 2 as well as their hilarious meet the "insert class name here" stuff, make sure you go to http://www.teamfortress.com