No particular order for these guys, given how subjective an exercise this is... but any dance party without one Rocky Horror track is just missing something ineffable. (No, BESIDES the Rocky Horror track. That's the effable part.)
Warrior Princess Excerpt by Gilbert and Sullivan, by Kevin Wald. Sing it yourself!
Banned From Argo by Leslie Fish.
Birdhouse In Your Soul by They Might be Giants.
Dream World by Lee Billings.
Heart of Glass by Blondie.
I've Had Enough by the Who. Obscure SF rock opera track.
Hell, pretty much ANYTHING by Leslie Fish.
Anything by John Williams.
Princes of the Universe by Queen.
Rhiannon by Fleetwood Mac.
Virtually anything by Doctor Demento.
Set Them Free by Sting. I just *like* it, okay?
She Blinded Me With Science by Thomas Dolby.
Star Trekkin' by The Firm.
The Space Between by Tracey Chapman.
The Touch from Transformers: The Movie.
Time Warp from The Rocky Horror Picture Show.
Almost anything by Weird Al Yankovic.
Ziggy Stardust by David Bowie.
That song David Bowie does in Labyrinth where he goes, "You remind me of the man," the other guy goes, "What man?" and the first guy goes, "The man with the power." You know it, right?
(In the interest of equal time... space... whatever, Tom the Fanboy recommends "Christmas at Ground Zero", "Attack of the Radioactive Hamsters from a Planet Near Mars", "Slime Creatures from Outer Space", "Everything you Know is Wrong", "Jurasic Park", "Nature Trail to Hell", "I think I'm a Clone Now", "Yoda", and "The Saga Begins"(sp?) as the best "sci-fi" songs in Weird Al's body of work...
and "My name is Kenny" says: "I don't see how you can get away with making a list like that and not include Pink Floyd somehow. I suppose you could also include a lot of techno, but in my opinion, techno barely crosses the line into music. Anyone can add a drum beat to a smoke alarm but it wouldn't be music. " Got an opinion of your own? Post it here.