Over the year I use a variety of "cheers" to use with the whole class or for an individual when they do something exciting.
Silent cheers: Raise the roof (hands go up towards the roof) disco (point to the corners and swing hips opposite direction)
Cheers w/ words and pantomime:
Trucker - Pull down on a horn and yell, "honk honk"
Roller coaster - hands slowly go up, up, up, then over two hills and say "chk, chk, chk, woooo, woooo"
Oreo cookie - twist the cookie, lick the inside, throw the outsides behind you and make a throwing away noise "choooo"
Attitude: snap fingers in a zig zag and say "mmm, mmm, mmm, mmmm, mmmm" w/ as much attitude as you can.
Cowboy - grab a laso and say "yippeee kay yi yay"
As I think of more, I'll post.
I use them when we all do something well or if a kid gets a right answer or does something kind I say "raise the roof for ____Name____ for __reason they get a cheer_____" or "trucker cheer for ___________ for ___________"