The cat we had when I was growing up was named Gwendolyn Callahan. She lived under the nursing home across the way and my mom would feed her a dish of milk; mom wanted a cat, but dad had said "no pets." He knew she was doing it, though, and one night as he tripped over the dish he swore and said something to the effect of "If you're gonna feed that damned Gwendolyn, at least do it in the house where I won't fall over the dish!" The Callahan part came from when my mom learned that Old Tom, one of the residents at the nursing home, had called her Callahan. SO, Gwendolyn Callahan. She had 4 kittens and we kept one, named Mimpy. She was supposed to be "Dimples" as she had a black spot where a beauty mark or dimple might be, but my 3 year old sister could only say "Mimples," and therefore Mimpy was her name. We only had Gwendolyn for about 3 years but we had Mimpy until I was about 20.
We got 2 kittens when DD was 7, at the very beginning of the Harry Potter craze. The black/white/grey cat with the lines on his head was Potter, and his brother, an orange tiger, was Weasley. DD named them. We had Potter for 17 years and Weasley for 20 years. Still miss our boys.
We currently are pet-sitting for DD's hamster as there is no space for her in the new apartment DD shares with her fiancee and his 4 year old son. She named her Mia Hamm-ster!