I love discovering new club ideas, especially when they aren't your traditional types of clubs :)
The ones I've used off the top of my head...
Ballet Class: For a story, it just helped get all of my little ballerinas in one place and dancing!
College Classes: I made several different types of college class clubs, also for story purposes. There was an Art class, a Library class, and I think I had a Farming class for the 1940's.
Family Reunion: I needed mods to increase club size for this one, but it was necessary so I could get my entire Sim family in one place for a reunion.
Highschool/Elementary: A lot like the college one.
I would like to eventually make a soup kitchen club, too.
