The Cat with Two Heads, by the Aquabats.
Frankenska, by the Toasters.
Radiation Song, by the Aquabats.
The Song of the Seven-Inch Cowboy, by Pain.
Yeah!
Hmmm, I suggest Frank Zappa’s “Cheepnis,” about a monster poodle that can’t be stopped by bullets or rockets, anything by Kraftwerk because they’re robots, most of the Devo oeuvre, and also anything by eX-Girl because they’re from the planet Kero Kero and write songs about spaceship fuel for their frog king and prehistoric vegetable wars and such.
Mad Professor by the Insane Clown Posse:
“I’'m lonely/I need a homie/So I got some limbs/And made me a zombie…”
Splitting the Genes by Uncle Bonsai (folk trio with brilliant, satiric lyrics; Tom Lehrer fans would probably like them)
Riding on the Rocket by Shonen Knife
Lots of stuff by Peter Schilling, but start with Lone Survivor, The Noah Plan and, of course, Major Tom (Coming Home)
[sub]And sometimes I think I’m the only person in the world who listens to all three of those.[/sub]
Einstein A Go Go by Landscape.
The entire Soft Bulletin album by the Flaming Lips. Including:
Good call. “Space food is marshmallow, asparagus, ice cream”. You can’t beat a wacky SK lyric. 
Flaming Lips “Race for the Prize” is a good counterpoint to all the mad scientist stuff (not meaning to break up the party, though).
“Two scientists were racing / For the good of all mankind”
“They’re just humans / With wives and children”
Gosh, my first simulpost. Thanks jjimm
My personal favourites are “Damnation Alley” and PXR5.
May I also add “Dr Stein” by Helloween to the list.
Was it as good for you as it was for me? Here, have a cigarette.
The very first, original recording of “Evita” has C.T. Wilkerson singing "The Lady’s Got Potential,’ including lyrics about Che’s new insecticide. A great hard rocking tune that was cut, but later included with different lyrics in the movie.