I used to post at a forum that was just about itself. It was origionally made by some nerd as a way for he and his friends to keep in touch online, be he started hosting a forum for a webcomic which no longer exists, and that attracted a solid user base (myself included). Eventually, I had my own section there (I won it). That was pretty fun- it was just supposed to be my own personal playground, but it actually became one of the most frequented sections there and spawned some pretty sweet threads (including "The Greatest Thread of all Time" and "101 Ways to Kill Kepp").