how about a tea challenge? drink tea, make tea, bitch about tea, dump hot tea on someone's lap....

or a challenge for passing as something the character isn't (be it sexual orientation, gender, nationality, or something kinkier).

i'd say a poetry challenge, but that might be a last resort -- so very many ways to go so wrong on that one.

or a letter challenge: write a whole story without using the letter 'i'. bet that'd keep people from running so far over the word limit!

a drunk and disorderly challenge might be fun.

what about a porn challenge? the characters must be having sex for the entire duration of the story!

gotta love cough medicine. how come other illnesses don't get such good drugs? there's a question for the ages.