This week BoingBoing posted a preview video of Zombie Wonderland, a zombie defense game for the iPhone. It looks like pretty simple gameplay with cartoony graphics. In between shooting out your windows at the approaching zombies and upgrading your weapons, you also have to clean up zombie guts (rendered as green puddles) off your floor.
Mokalus of Borg
PS - The video also shows a Roomba-like device that can clean the guts for you.
PPS - Seems like it might be fun.