The chicken sort. Mister G seems pretty much okay in himself so far - a little subdued, but nothing too dramatic. It's probably a good thing to get it out of the way while he's still so young although it sucks to see the poor wee bean covered in spots.
Are there any other childhood diseases to tick off on the list these days? When I was a kid it was chickenpox and mumps, but G has had his mumps vaccination so I guess hamster faces are a historical relic around here (a good thing. My mum took me school shoe shopping with my massive round face and the reassurance that 'nobody will realise, they'll just think that's how you look'. Win.)
Last I heard (by which I mean, in the 1980s when I had it) calamine lotion was the way to go, but I don't think there's much else to be done other than sitting it out and lifting the time limit on Sesame Street videos.