It's a baby guinea pig (also called a cavy). Isn't he adorable? Oh, c'mon, even it you don't like rodents, he's awfully cute. His name is Kramer (after the character on "Seinfeld") because he has crazy hair. His hair doesn't lay smooth like his parents and one sibling. Instead, he has swirls and cowlicks, like two other siblings.
Son #2's friend has a pair of guinea pigs and they had babies. Son #2 first met Kramer when he was only 3 days old. He's grown fast, though, and is old enough to be separated from his mother so the friend's mom offered one to us. We picked him up last Friday (my criteria: I wanted the friendliest, mellowest one).
It's funny how expensive a 'free' guinea pig can be once you factor in all the accoutrement. He's loads of fun, though. Really sweet.
Here's another photo: