There's also a 'Filk' version floating about (I can't remember the author) with verses like:

Morbius and Alterra were living all alone,
With half a world of generators just to power their home.
But when she loved a sailor (as the nice girls often do)
Daddy pushed a button, and the whole kaboodle blew.

Gandalf was a light-show man to make your parties swing.
He hung around the night clubs where the elven groupies sing.
A rumble in a cellar bar gave him such a fright
He got born again from Manway, and changed his robe to white.

Chorus:
Filk fen*, fake fen, neo-fen and all
Come to our convention and have yourselves a ball.
Check your swords and dungeon-plans and phasers at the door
And we'll sing you science fiction songs you've never heard brfore

I'll try and find the original

*fen = plural of 'fan' (as in man/men)