Inside Joke and you're on the Outside. Used on someone looking for an explanation of an inside joke. Usually leads to further confusion, as it is often use as an inside joke of its own.
Guy: Jane sure is bootylicious.
Guy 2: That thing is like a watermelon!
Girl: What are you guys talking about?
Guy: I J and you're on the O.
Known throughout the world as a dance or jig similar to that in the Charlie Brown cartoons. Performed by shuffling your feet back and forth while analyzing the ground (world). Can also be modified by spinning a basketball on the tip of your finger - resembling the world spinning on its axis.
I was making a supreme pizza at work and two fellas came in and instead of ordering proceeded to do the "o the world just keeps on spinnin".