Yea! SouthPARK!!! Actually, whatever you put in your forum should be your choice and you can therefore make catagories for any of your own favourite subjects. Try music, computers and gaming for a start...
Iceman, there are too many of those on the web. I'd say make your site about something you really like. It could be Southpark, Yu Gi Oh, or toilet seats.
Or provide something no-one else can. Provide jokes made by you or friends that not many other people know. Provide interesting insights in any matters that you choose... get that special something that can be found no-where else.