It appears that on www.pogo.com, you can sign up for free and play monopoly online with your friends/enemies. This opens up quite a range of opportunities for play with a webcam from basic strip games through to wet and messy ones, or a mix of both!

How about the following:

Pay rent on a property: Truth question from each player
Pay rent on a property with houses: Take off an item of clothing (get wet if already naked)
Pay rent on a property with hotels: Get completely naked (get messy if already naked)
Pass go: nominate someone to do a forfeit/take something off OR put an item of clothing back on yourself
Free parking: Jerk off for thirty seconds
Just Visiting jail: Get wet no matter what you're wearing
In jail: Get messy
Bankrupt/Loser of game: naked, messy, and jerk off.