Moshing (Mosh pits) can be expressed in many different ways at concerts, gigs, clubs, etc..
The first mosh was pushing each other with the palm of your hands inside a circle of people but now days has transformed into people punching, kicking, and even flipping themselves into others. No matter how violent the mosh may look, people who fall down are normally pulled straight back up by others in the pit. Also gives you an amazing rush.
A: It all went so fast, I only remember hitting a guy in the back of his head in the mosh last night.