Hare Scramble
Closed-course off-road race in which riders go fast for 2-3 hours on a course
laid out primarily in the woods.  Course length normally varies between 3 and
20 miles and includes all sorts of fun stuff like mud, steep hills, rocks, trees,
creeks, rivers, and lots of crashing (well, that's mostly me). The object is to
complete the most laps within the time period, and as long as you reach the
main scoring area prior to the time cut-off, then you keep doing laps until one
of the following occurs:

1. Time runs out
2. You break something important on your bike and quit
3. You break something important on your body and quit
4. Combination of 2 and 3 above
5. You run out of energy and say "I will be leaving now"

Enduro
Off-road race in which the goal is to maintain an average speed (defined by the
promoters) over the entire course.  Course length is often a 30-40 mile loop
run twice, but can be longer.  Riders are checked at various points throughout
the course (riders almost never know where the checks are located) and
points are added to the overall score if a rider is early or late.  Penalties for
being early are far more severe than for being late.  The object is to receive the
lowest score, kind of like golf except it's not boring.

Motocross
An off-road sport with origins in Southern California, also known as Land of
People Enjoying Spinal Injuries.  The courses involve many sharp turns and
large jumps, and most are set up with laps that the fast guys can do in 2-3
minutes.  Spectators can usually view most, if not all, of the crashing, I mean
racing, from the same vantage point.  Indoor motocross is called Supercross
or ArenaCross.

Freestyle Motocross (FMX)
This motocross derivative has been popularized by Travis Pastrana and
ESPN's X-Games.  The object of this competition is to jump huge and while in
mid-air, remove your body as far as possible from the motorcycle and get back
on the bike before landing.  At a FMX competition, Travis Pastrana once
separated his spine from his pelvis.  That is correct, HE SEPARATED HIS
SPINE FROM HIS PELVIS.  During a 6-month recovery period, Travis was
filmed bragging that he had his wheelchair up to 25 mph (or therabout).  Travis
finally lost an FMX competition in 2003 after he knocked himself silly
attempting a backflip/360 combo. That is correct, HE FLIPPED HIS BIKE
UPSIDE DOWN WHILE ROTATING THE BIKE 360 DEGREES IN MID-AIR,
WITH HIS BODY STILL ATTACHED TO THE MOTORCYCLE.

Classes
Pretty simple, really.  You've got your fast guys, your slow guys, and the guys in
between.  The A class is  fast guys, the C class is the slow guys, and the B
class is intermediate level.  Also, there's a AA class for the insanely fast pro
riders.  The classes are then divided between engine sizes, usually small
bikes (up to 200cc), medium sized bikes (201-250cc) and big bikes (over
250cc).  Then there's a special class for 4-stroke engines.  Then there's age
groups, mostly for more "mature" guys, like Vet, Senior, Super Senior,
Super-Duper Extra Special Senior, and the very popular Hip Replacement
Class.  Then there's classes for mini-bikes, women, and beginners, and for
people who just want to sit by the trail and drink beer.  So basically, each event
has exactly 247 classes and the only guys who go home without trophies are
white males in their late-20's with German heritage and dark hair riding orange
European dirt bikes with 300cc engines and Michelin front tires.
Off-road Racing Terms Defined