Youngme / Nowme is an art project where people post pictures of themselves now, recreating pictures taken of them when they were young. They’re a bit hit or miss, and there’s a fair number of missing / broken pictures, but a few of them are absolutely great.
A few favorites (I know, lame link text, but I don’t want to give them away): here, here, here, here, here, here, here, here, and here.
Kind of makes me want to dig up some baby pictures. Whole collection here.