ORIGINAL: quiksilver
I've always been a fan of the silent fist pump. Sometimes a fist-pump in a downward punching manner with an audible "Boom!"
Not sure why "boom." There is really no booming. I say "BOOM!" anyway. I'm crazy like that.
I'm a big fan of boom too, but I go a little further with "Boom goes the dynamite!" At the same time I put both fists over my head and shake my ass....just a little.