Just finished another MTB XC Biathlon. These are XC races combined with olympic biathlon stye target shooting.(using air rifles of course.)
Ride 2 laps, (4 miles each) shoot 5 targets, run a penalty lap (100m for every missed target), ride another lap, shoot again, ride another lap and finish. These events are fantastic fun and as far as I know they don't exist anywhere else in the world. There were over 300 folks of different age categories but not divided by racing class. You get to go up against some of the faster riders in other classes.
I know I wrote about this before but I just want to spread the idea. I would love to see this event elsewhere.