(noun.) uncontrollable hairtrigger laughter.  known to occur at slumber parties after the topless pillowfight.
after we started talking about how weird our chemistry teacher is, tamara flung a tampon at jamie.  after that it was pretty much a nonstop gigglefest
by king kong NINJA April 20, 2004
 Get the gigglefestmug.
Get the gigglefestmug.