Origin of the word 'gay'

Okay, my Gramps was the first to tell me this fact, but the word 'gay' as a word to describe homosexuals actually is an acronym that means 'Good As You'. I didn't get an exact date for this one, but from the conversation, me thinks somewhere in the 60's he heard about this (although after a bit of a search on the interweb, it actually seems to go back to 1910s or 1920s). Interesting though eh?