Hamsters are delightful little pets that can be purchased, along with their necessary supplies, at several pet stores around town. They look pretty cute inside little hamster balls - round plastic containers that allow them to be (relatively) safely mobile. With the hamster balls came the next obvious step: racing them! Several companies make 'race tracks'.
In Davis, there are two main events.
The hometown one is at the Farmer's Market. In April, 2007, they held the first annual UC Davis pre-picnic day Hamster Ball Races, where a hamster named Zeus won first place. 
It also happened the Saturday before Picnic Day 2009 where Chris Dietrich had the distinct honor of emceeing the exciting races. A hamster named buttercup took the top prize that year. Has this event continued?
The other event is the annual Hamster Ball Derby hosted by and at Petco (at many stores nationally, including Davis) for over a decade.
Both events are marketed primarily towards children with pet hamsters, though sometimes side-competitions are held with mice, rats, and guinea pigs. These races are exciting in a similar way that the Doxie Racing during picnic day is - you never know what'll happen. The following video is one of the first round races at Petco's Hamster Ball Derby in 2006: click here to watch.
