Short ones
1. Funniest gym face you can make
2. Sports Game predictions (who will win, what the score will be as tie breaker, for the NBA and NHL finals) and when football season rolls around if this is still going on, you predict the winners of every game that week, and whoever gets the most rite wins, if you get em all correct, you win that prize + another item
3. Something Movie related, like a picture from your favorite movie, and why this movie is your favorite, or your top 5 movies and why or your favorite of a couple genres and why, like for example your favorite comedy, sci-fi, action, drama, and the person with the most detailed. or creative answer wins.. (this one may be tough)
4. Inspirational quotes/pictures you post one a day for x amount of days, and for every original one (if someone copies yours or it's a repeat it doesn't count as an entry) and after x amount of days you pick x amount of winners randomly...
5. Funniest memes about a certain subject is always fun
6. Post your short term, medium term, and long term goals and how you are going to achieve those goals and the best answer/s win a stack that will help them achieve those goals.
6.5 A slight change to the one above, you have 3 stacks, one for a cut, one for a re-comp, one for a bulk, you pick a stack you would want to win and how it will help you achieve your goals, best answer deemed by you wins for each stack.
Long term
1. The best transformation over a set period of time.
I'll try to think of more later, this is what I got off the top of my head.