Rightfully hailed as "the greatest band on Earth," the super-sized acoustic metal/comedy duo Tenacious D was an unlikely success story. Actually, Tenacious D was probably so successful precisely because they were so unlikely: few people would imagine that two chunky guys bashing on acoustic guitars, singing songs like a tribute to the greatest song in the world (because they forgot how the greatest song in the world went after conquering the Devil with it) became one of the biggest cult bands of the late '90s and 2000s.