The Boulder Boulder 10K is the largest race in the US in which all participants are timed, and after receiving 54,000 runners in last year's event, the 2012 Bolder Boulder could include even more participants in its 92 different heats. The race is huge, but by breaking things up into 92 smaller races, people are allowed to find their own pace. According to the event website, there are six basic categories of racers: qualified runners (ones with proof they can run under 68 minutes), runners, joggers, jog/walkers, walk/joggers and walkers.
Estimated finish time determines each racer's category. Online and mail-based registrations are already closed, but if you would like to get involved there is still time to register in-person. You can do so at the BolderBOULDER Twenty Ninth Street store in Boulder, CO through May 25, on race weekend at the Pearl Street Mall SportsEXHIBIT or on race day.
If you aren't interested in running the race, there is still plenty of entertainment along the route. Entertainers like bands and belly dancers will line the race route and provide free entertainment for the runners and the crowd. For a calendar of events, race schedules and start times, click here.