Synopsis
The song chronicles the band members' encounter with a demon who demands the duo play "the best song in the world" or have their souls eaten. Having nothing to lose from trying, they "play the first thing that came to our heads", and it "Just so happened to be / The best song in the world."
Given the "Stairway to Heaven" interlude in the original TV series version, it might be suggesting the best song in the world is indeed that song, but the lyrics make clear that the song Tenacious D is playing sounds nothing like the song they came up with to please the demon (specifically, "This is not / The greatest song in the world, no / This is just a tribute"). However, since the following lyrics are "Couldn't remember / The Greatest Song in the World, no, no /" it's possible that the best song was, in fact, "Stairway to Heaven" and they couldn't remember that it was what they played.
In an interview the band claimed that the inspiration from the song came after Jack Black played Metallica's "One" for Kyle Gass, describing it as "the best song in the world", leading to a failed attempt to themselves write an even better song, and a discussion of the meaninglessness of labeling any song that way. "Tribute" was written to make the claim that the greatest song in the world had, in fact, been theirs but they had forgotten it, as a paean to the impossibility of reaching musical perfection.
In Tenacious D in The Pick of Destiny, it is implied that the climax of the movie, a rock-off challenge between Satan and Tenacious D told through the song "Beelzeboss (The Final Showdown)", is indeed the incident chronicled in "Tribute", and that the portion of "Beelzeboss" performed by Tenacious D is the song receiving tribute. After defeating Satan, Jack and Kyle recall the incident once more, describing it as, "the greatest song in the world". Unfortunately, they are unable to remember how it went. Also in the song Beelzeboss, they mention that they know the demon's weakness, referred to as their "rocket sauce", which is what they use in their HBO television series to defeat the demon. However, unlike the demon in the television episode, Satan says they are "Fuckin' lame" and tries to take Kyle Gass to hell after all, while the demon asks if they are angels. However, considering that they do not remember the song, they may have forgotten this as well. This was confirmed in a commentary with Jack Black for the movie.
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