Just drop by, leaving a list of some clubs I created in the past:
-a gaming club with the main activities being playing video games and watching tv/movies
-a wellness club. It's very self explanatory
-a bro club, only sims with the bro trait can join (I actually like that trait and don't understand all the hate), they were usually doing anything which has to do with sports.
-a family club with members of one family who would usually go out to eat something or go bowling
-a party club (self explanatory again)
Some teen club ideas I already tried out:
-a cheerleading club - some teen girls meeting at the sports ground to dance
-an emo club - teens dressed all in black, playing musical instruments and writing depressing poems
-a basketball club - teens who would play basketball and play video games
-a "popular kids" club - actually just the paragons, but with my own sims. They would mostly just try out new outfits, dance or singing karaoke. They are enemies with the basketball club, much fun!
I still plan to make a karaoke club, but I didn't do it yet.
It's especially fun when you have this mod which adds more club icons:
https://zerbu.tumblr.com/post/160488483060/the-sims-get-together-mod-more-club-iconsSadly, it won't add anything new to the club doors, otherwise it would be perfect.