This looks to be a take off on the Atomic Cycles Event Calendar, http://www.atomiccycles.com/event.html This Southern California group has been running coaster brake off road races for years. The bikes are all one speed coaster brake equipped with no front brake. Their videos are great to watch since no one has very good braking and they go very fast over varied terrain. It is not modern downhill type mountain biking that use suspended disc braked bikes. It is very competitive and most people are using older steel klunkers. Have fun with this.