Vermont Goldsprints primarily uses Opensprints software and hardware. That means we have two bikes on rollers. There are no front wheels, there's no balancing required, and the forks are bolted down. The rollers each have a magnet which passes a sensor. The sensor is connected to an OpenSprints box containing an Arduino board with a bit of custom firmware, and that is connected to a computer running the Opensprints program. The program displays the progress of the racers on a big "clock face" and also records everybody's fastest time.
In a typical event, we sign everybody up and get them into the computer, and then run people off in more or less random head to head contests. This lets us get a time for everybody and ensures that everyone who is signed up gets at least one ride on the bikes.
Then, we take the four fastest men and the four fastest women and set up a finals bracket, usually racing #1 vs. #4 and #2 vs. #3 in a quarterfinal and then a final and a consolation race.
The whole thing, for a decent-size crowd, might take about an hour and a half from start to finish.