Acronym for Fucking Shot Time
"I was hammered from all those FSTs"
"Who wants to join me in a little FST?!"
"I always make room for a little FST"
A Fan SoundTrack. In short, a mix CD / MP3 compilation whose songs and / or music is dedicated to a particular fandom or attribute of that fandom, such as a certain paring, or an episode, chapter, arc, or scene. Usually made open for public download by uploading the individual / compressed file(s) to public file sharing websites, such as rapidshare, megaupload, or by using torrents.
Let me know when you're done making that FST for Superman, 'cause I wanna download that shit ASAP.