When playing baseball, we would mess around and do the pre-swing waggle like Gary Sheffield (he has been around since '88).
We all tried the Jordan fade away jumper, but for some reason, we couldn't quite match the elevation he had on his version.
I can't quite think of anything particular for football, but when being quarterback, I remember shouting out "Blue 32, Blue 32, set, hut!" like Scott Bakula from Necessary Roughness.
Great thread, it's nice to reminisce.