Here's a comp. for the forum's comedy writers. It's pay entry, and only one winner, but it looks interesting anyway:
http://leafbooks.co.uk/writers/competitions/humourcomp.html
This is one for Leevil:
http://www.hotspotbooks.co.uk/?hot=Erotic%20Fiction
The example submissions they display are hillarious. Extract:
"Sometimes I would go to a prostitute and pay to be punished...She gave me a wank, that was nice."
Easy money.