Yet another chat spin off thread.
Here's The Firm singing Star Trekkin', which at one time at least was de riguer at every sci-fi convention around here
Leslie Fish's Banned From Argo (courtesy of OtakuLoki)
Edelweiss's Starship Edelweiss (courtesy of Vox Imperatoris)
This next one is a bit NSFW, you've been warned.
Star Trek Rap featuring Prime Directive and Galaxy Class
There must be loads more!