Hi, Zosime-san! Welcome to the host club!
Azula's right, most of the activity takes place in the main roleplay thread, though you can request smaller interactions in either of our two sub-forums that are designed for that: Tamaki's Mind Theater (for non-hosting interaction) or Music Room Three (for hosting).
We do have a bunch of players who are part of various clubs, but no one has yet started any specific threads or requested a forum for other clubs. We're very much a please-feel-free-to-start! kind of place, so if there's something you'd like to start up with some of the other clubs, by all means go for it! I know we have plenty of people in the art club, the music club, and even a couple in the black magic club ...