Ultra distance mountain bike racing has really taken off the last few years. The Leadville 100 Mountain Bike Race has been around a number of years but now it is very difficult to get in. The Vail Ultra 100 is no longer but was run for a number of years. Other 100 mile mountain bike races have popped all over the country and a series has been created. It seems like as ultra distance races become popular other longer races start to show up. Just like Colorado Trail Race. Now that is some serious distance.