What exactly is bmx ?
BMX is the name of a popular bicycle used for both casual riding and sport, and designed mainly for dirt and motocross cycling. "BMX" is the usual abbreviation for bicycle motocross.You can read more: http://en.wikipedia.org/wiki/BMX_bike
Bicycle motor cross. Free style on a bike..
Bicycle Mortor X...algebra problem: X=cross
doing tricks on a bike ....? a small bike haha.