My cat--who originally belonged to my former roommate--is named Rowan, which apparently is a name from an Anne Rice novel that he (the roommate, not the cat) liked. He only gets called "Rowan" when he's in trouble, though; the name he usually goes by is Tub (because he's a touch, er, hefty).
My parents' chickens are the ones with the most interesting names, though:
roosters: Buster (that's my baby), Jim, Dennis, and Whitey
hens: Lucy, White Chicken, Myra, Chickie, Alex, Dee, and Bob. Bob was part of a pair of hens that my brother named Hank and Bob. Why? We're not sure.
Oh, and their cat (female) is named Chopper. When we first found her, we thought she was a boy (she was only 4 weeks old and really tiny; her wild mother had had to be put down after something attacked her) and I wanted to name her after one of my favorite hockey players, Al MacInnis, who is nicknamed Chopper. For a
boy cat, it seemed OK.

She also goes by Chomp, which is what one of my mom's tutoring students thought her name was.
They also adopted her brother, who we thought was a girl, and my dad named him Lizzie. (No idea why.) When we finally realized that he was a boy, we didn't want to confuse him, so we shortened it to Izzy, which we justified by saying he was named after Jason Isringhausen (Cardinals closer). We told my great aunt Isabella that Izzy was actually named after her, though; she was tickled to no end by that one.