Highschool of the Dead is an interesting one to say the least. It started off as a crazy and violent manga about a bunch of high schoolers and the school nurse trying to survive a zombie apocalypse (read the first volume online and wow, its just about everything you need a zombie comic). Now, it has arrived as anime recently, airing its first episode and it is just as nuts as the comic it is based off of.
Now I normally don't bring up anime tv shows around since I never find anything that may appeal to anyone or they may not be up anyone's alley. However, a show about zombies and people killing or getting killed by zombies always seems to spark people's interest. So, here it is, the first episode I could find. Heads up: This is in Japanese with English subtitles.