Nigel Tufnel: The numbers all go to eleven. Look, right across the board, eleven, eleven, eleven and...
Marty DiBergi: Oh, I see. And most amps go up to ten?
Nigel Tufnel: Exactly.
Marty DiBergi: Does that mean it's louder? Is it any louder?
Nigel Tufnel: Well, it's one louder, isn't it? It's not ten. You see, most blokes, you know, will be playing at ten. You're on ten here, all the way up, all the way up, all the way up, you're on ten on your guitar. Where can you go from there? Where?
Marty DiBergi: I don't know.
Nigel Tufnel: Nowhere. Exactly. What we do is, if we need that extra push over the cliff, you know what we do?
Marty DiBergi: Put it up to eleven.
Nigel Tufnel: Eleven. Exactly. One louder.
Marty DiBergi: Why don't you just make ten louder and make ten be the top number and make that a little louder?
Nigel Tufnel: [pause] These go to eleven.
The band Spinal Tap isn't the only popular group of fictional musicians. Here's Spinner's list of Top 23 Fake Bands, which includes everything from Homer Simpson's barbershop quartet to Bill and Ted's Wyld Stallyns to this video:
In addition to fictional music groups, there are also fictional songs, albums, orchestral works, and operas. This famous song is from a fictional opera, Hannibal by Chalumeau, in Phantom of the Opera: