Sanctum is a mix of a First Person Shooter and Tower Defense, playable through Steam ($9.99 Mac and PC). You have a build phase where you are given resources and you may build towers. The battle phase is a little different than normal tower defense games. Before the game starts you are given a choice of 6 guns. Here, during the battle phase, you can use them. If you want to try it out before you buy it, there is a demo in which you can play a round. I have been playing it a little, and have done online play, but I want to get a group of Blocktopians to do this. It's an awesome game with great graphics and gameplay. If possible, I would like a group to play a round or two every Saturday. If you want to do this, just tell me; the first three who apply get in. I hope to see you in Sanctum!