This is a game I liked so much, I bought it twice. I got the Mac version when it came out and I loved it, but I was low on free-time-in-front-of-the-computer and so it languished. But when it came out on the iPhone [iTunes link] I bought it again and the combination of commute-playability and zombie-cuteness made it easy to plow through. It's in the category of "tower defense games"—where you have little direct effect on the attacking hordes of, in the case, zombies, but you can plant (literally, in this case) defenses in their way.
FuzzyCo grade: A