Thats got to be homage to the WKRP episode with Scum Of The Earth.
Riverbottom Nightmare Band!
You know, from Emmett Otter’s Jug Band Christmas.
You know, that Christmas special Jim Henson did.
Kermit had a cameo.
Oh, fuck it.
Gotta second this – how many other bands end up bringing about world peace and a new direction for human development with their most excellent music? 
A mess o’ Mama, mess o’ Mama, mess o’ Mama’s Barbecue!!
Waterman
I believe the Archies were pre-dated by the Banana Splits.
:: showing my musical cultcha ::
The Commitments.
in no particular order:
Wyld Stallyns
The Boils (from How To Get Ahead In Advertising
Breaking Glass (from the film of the same name)
and I can’t believe someone beat me to The Nowtones (curse you, RealityChuck!) (BLOTTO rules!)
(btw, Chuck, if you have ever been able to decipher the whole text on the album cover, please send me a copy, would ya?)
Bo
I wonder if they ever got Eddie Van Halen to jam with them? 
Donny’s Band from EuroTrip.
(Yes I know it’s a band called Lustra in real life)
But the song is damned funny tho.
Wyld Stallions
LimoZeen (of sbemail fame)
The one from “GTA: Vice city” (with the “Steel heart stone cold prostate tour”)
and, finally: Zoneyes, a band I just made up. They totally rock.
Not a favorite, but does anyone else remember a 1992 Fox series called The Heights? It had a hit song called “How Do You Talk to An Angel.” The song was a bigger hit than the show (which only lasted twelve episodes), and got lots of radio airplay.
Happy Kyne and the Mirthmakers, the house band on Fernwood 2-Nite.
Strong Negative Correlation, a band that I made up in high school and spent some time trying to get people to believe in. I had some great song titles, and I wish I still had them.
If Spinal Tap is still considered a fake band, then so is Tenacious D.
And The D is clearly, clearly, the greatest band in the world, fake or otherwise.
Puscifer (also known as Tool) and Titannica from Mr. Show.
Titannica actually recorded a couple of songs, again with Maynard on vocals. Apparently he’s good buddies with Bob and David.
Unless I’m mistaken, that would be Love Fist, and I second that nomination.
The Patry Posse, with Bart as the front man.
And the greatest boyband of all time, The Meaty Cheesy Boys.
The Enemys, a beat group that appeared on The Beverly Hillbillies. They were one of those mid-60s garage bands that played stuff like “Got My Mojo Working”, etc. The Clampetts decided to bring them to the mansion and play at their wing-ding. I think they played a song called “Wing-Ding”…interesting trivia: that group featured a young Cory Wells, who went on to fame with Three Dog Night.
Actually, their music was from a real band but (IIRC) only one of the four playing the band was a real musician.
As it turns out, “Dog” was the one played by the real musician.