I had a brief fling with zettai ryouiki a while back--I might revisit it. (It was fun... if only I'd properly tagged and filed the socks I finally came up with!)
Now young Japanese women are selling that space for advertising. (This is RL... though I wonder whether one could do that in Second Life? UPDATE: of course you can; that's what tattoos are for... but would it show up backwards on your other leg?) They must be at least 18, and have at least 20 friends on social networks. More info at the New York Post.