For any rider, N+1 is the optimal number of MTB bikes to own.

Where N is the number you have now... I.E. one more is always good!

Garage Sale: When your crash is so bad they find you by following the trail of debris you left behind in your path. "a pedal broke off, lost my chain, my pack ripped open and I lost all my tools....it was a total garage sale!".

Wide Open: Refers to a type of track/trail that is wide, allowing the rider to choose from multiple lines. It's pretty much the opposite to singletrack.

Wadded Up: A crash where you and your bike stay friendly - too friendly - for the entire experience. Comes from the concept of crumpling up paper into a wad.

Trail Nazis - People/walkers that intentionaly sabotage trails in an attempt to injure or deter riders from using the trails, eg. "The Trail Nazi's have been busy, look at those logs".

Trail Fairies: Used "The Trial Fairies have been out" When you go down a track you know well but there are changes to it to you weren't aware of.

Taco'ed Wheel: To damage your wheel to deform it's shape in any way which deems it unrideable (ie. bend it so far it resembles a taco shell).

Stoppie: At speed, the front brake is applied and the bike lurches onto the front wheel until stopped... or you go over the bars (endo).

Step-up: A double jump or gap where the height of the kicker is lower than that of the landing.

Step-down: A double jump or gap where the height of the kicker is higher than that of the landing.