Geronimo is gone now, and we're all very sad and miss him. He was a great pet. Because I was so sad about the loss, Michael went out and got another hamster! Despite my family's advice to just name him "Geronimo II" so we could keep his name on the cage, we decided on Ike. Ike the Hamster. Mike and Ike (and Sarah). We think it fits him nicely.
He is a little smaller than Geronimo (though we've been told Geronimo's large size can be attributed to his affinity for Cheerios), and seems to be a lot faster. We're still getting to know him, but so far he seems like a pretty cool little guy.