Head over to www.redvsblue.com
and watch a few episodes. It's an internet series. Basically, a bunch of guys have filmed stuff from Halo and put their own voices to create their own situations. One of the characters is named Private Michael J. Caboose. Shortened down, it becomes Pvt Caboose and he's my favourite character. Then the '91' is drawn from my year of birth, 1991.