ScrewAttack.com's "Top 10 Video Game Themes EVER!": they play the first three notes of World 1-1, pause, and then claim that they "don't even need to play any more, 'cause you already know what it is!" But they do anyway.
It's also played in Luigis Mansion; when Luigi taps on the instruments in the Conservatory, summoning the ghostly pianist Melody Pianissima, they play the tune. (After talking to him, Melody herself then plays either the underwater music from the original game or the athletic music from Super Mario Bros. 3, then asks a question about the meaning of the tune. A wrong answer means she gets angry and vanishes (meaning the player has to repeat the process) while a correct one means she attacks Luigi, but becomes vulnerable to the Poltergust 3000.