Anyway, I'll explain for you about how we handle themes in Roczuz.
Because we are a general talk we don't really have a niche, however many of us enjoy similar things so what we do is that from time to time we vote for video game, tv series, etc that we like and then we try to make our community to appear as if it was dedicated to it.
For example, if we choose "Pokemon" as our theme, I'd make a pokemon skin for the community and pokemon related contests. Members would change their avatars and names to pokemon related things if they wanted to and by the end of it we'd give out some prizes for the best avatar/banner sets and winning/participating in our contests. It is great, really... when there are several people willing to try.
Last theme we had was Zelda. I thought I would close Roczuz for good after it and I wanted to go with a bang. It was not nearly as good as the past ones and in a way I did quit after the contest but decided to leave the community open anyway, which is why I haven't really advertised of late. :(