Court Jesters.

[zabado]

1. Does the saying "pull the other leg, it's got bells on" have anything to do with court jesters .If not where does the saying come from?.

2. When and why did people start to "wave" their friends goodbye?.

[HowardKennitby]

Cassell's Slang Dict lists it as being from 1960s. No derivation given.

[Quizmonster]

Click http://www.worldwidewords.org/qa/qa-pul2.htm for an answer from a noted etymologist and lexicographer.
Waving appears to be virtually universal, so any prospect of finding out when and why it originated is pretty remote. If it was really "Goodbye" - ie probably never to return - the raised hand might conceivably have represented a protection over the head of the one leaving...a sort of divine umbrella.