Legend has it that the initial creative spark for This is Spinal Tap was generated from a serendipitous moment at the Chateau Marmont in 1974, when Christopher Guest overheard the following “duncelike” dialogue between the bassist for a rock band and his manager:
 

Manager: All right, well, we’ll take our instruments up to the room.
Bassist: Don’t know where my bass is.
Manager: I beg your pardon.
Bassist: I don’t know where the bass is.
Manager: Where is it?
Bassist: I think it’s at the airport.
Manager: You have to get back there, don’t you?
Bassist: I don’t know, do I?
Manager: I think you better.
Bassist: Where’s my bass?
Manager: It’s at the airport.

 
Guest let that idea ping-pong around his head for a while, and in 1978 Spinal Tap made its first appearance on an ABC sketch program called The TV Show, which aired at 11:30 pm. The initial target of the sketch was an NBC music show called The Midnight Special. In the book Risky Business: Rock in Film, R. Serge Denisoff and William D. Romanowski explain that the three main characters of the band were developed during video shoot. According to Harry Shearer (bassist Derek Smalls), “We were shooting a takeoff on ‘Midnight Special,’ just lying on the ground waiting for the machine that was supposed to make the fog effect to stop dripping hot oil on us—and to relieve the tension of that moment, we started ad-libbing these characters.”

In the clip, Rob Reiner introduces the band not as “Marty DiBergi” but as Wolfman Jack. The video is a kind of repository of heavy metal video tropes—the endless over-emoting on stage, the quasi-choreographed physical interplay between the band’s members, a video montage including a trippy poker game and a death’s-head judge pronouncing the band to be “guilty,” complete with gavel. There’s also a sublime Busby Berkeley moment that no real heavy metal band would ever be caught dead executing—this is the reference to “lying on the ground” in Shearer’s comment above. And just to top it off, there’s a shot of a playing card—the ace of spades, natch—on fire.

You can’t tell from watching it—at least, I can’t—but the keyboardist in the video is none other than Loudon Wainwright III.
 

Previously on Dangerous Minds:
Spinal Tap’s IMDB rating goes to 11
LEGO ‘This Is Spinal Tap’: Nigel’s Guitar Room