I watched a show on the Discovery Channel a few months ago on a two-headed girl (well, two girls with one body I suppose). They were around 10 years old and played volleyball and shit. It was incredibly strange watching them play, but somehow they managed to coordinate their movements well enough to hit the ball. I think they were in the process of having their spines fused or something to make it easier to move - or maybe the opposite, I'm not really sure. Still, it was interesting.