Siteswap

There's juggling for jocks, and then there's juggling for nerds: "Siteswap (also called Cambridge notation in the United Kingdom) is a notation used to describe juggling patterns. It encodes the number of beats of each throw, which is related to their height, and the hand to which the throw is to be made. It is an invaluable tool in determining which combinations of throws yield valid juggling patterns for a given number of objects."

Even if you can't juggle yourself, you can still pretend thanks to Siteswap.net's JsJuggle.