Just got Atom Zombie Smasher as a gift.
Picture a tower defense game, where you and the monsters are inside the tower, and you're trying to get the fuck out. That's about the size of it... You set things up like infantry and barricades, call in this rescue heli, try and rescue as many survivors as you can before the zombies infect them, and get out.
Lot of fun. And it's a different experience each time, with randomly given options and such..