Why not hold monthly contests for pictures or videos? Have a theme or something. Like a most daring video or hottest ass picture and the pictures or videos would be voted upon, and the winner get something like a month free subscription. Or get something to put on their profile page. Maybe it would be easier for viewers to have a special contest tab or a seperate page to view them on instead of getting mixed up in the rest of the videos or pictures.

Some suggestions.
Most daring or public
Best outdoor or nature
Hottest halloween costume
Best Creampie
Strangest Object insertion
Best Lingerie

Anyone else have any suggestions for a good contest?