I'm a member of the FSL (technically ex-member, since I graduated UTD nearly a year ago, but I still troll^H^H^H^H^Hhang out in the IRC channel), and we make fun of the name ourselves.
The FSLUTD name is new--we were the Linux Users Group (or UTDLUG for shot) until last summer, when someone decided to change the name to get us more attention.
I still maintain that we should invent a protocol called SLUT, and write the Free SLUT Daemon :P