Servo quietly hums the theme from “Charlie’s Angels” while the knockoff version from the movie plays on the soundtrack.
and
“Vague-ly Strauss… but not!!”
One of my favorites is in Sampson vs the Vampire Women. The leading lady plays the Moonlight Sonata and the riff is “Beethoven, from beyond the grave, renounces his great work”
I guess the riffs that have to do with background music stick in my mind the most.
In Time of the Apes, where the movie soundtrack sounds like the song “Pop Muzik” and they sing along.
Not sure if these are favorites, but since April is for Alice (Cooper) for me, here’s a few, with a little help from Annotated MST…
From Starcrash
[Sung] School’s out … for Starcrash …
From Robot Monster
[Announcer voice] Solar flares of the end of the Earth. Even at the end of the world, love springs eternal.
[Bot] Man needs woman to be his steed. Woman needs man, yeah, now she got the need. –Is that right, Joel? –I think it’s something like that. It’s an old Alice Cooper song.
Yongary had several music riffs, including one for Alice, but since they haven’t annotated that I don’t know/remember if it was just a name drop or a song sung or referenced.
I could never limit an answer to just ONE riff, but the first one that jumps to mind is the god-tier “Kung Fu Fighting” riff as the hubby listlessly muddles around on the piano in the “Once Upon a Honeymoon” short from Night of the Blood Beast.