When I was about 12, there was a major rumor that Jon Bon Jovi went on MTV and announced that he was Gay.
And of course there's the one about Frank Zappa winning a "gross out contest" with a fan onstage. I won't tell the tale but some here must have heard it.
That one's obviously false (or the number has been exaggerated over time). Twenty quarts is 640 ounces, or the equivalent of 53 bottles of beer. No stomach can hold that much.
That Rod Stewart rumour has also been attributed to David Bowie, Elton John (more believable), Alanis Morrissette, L'il Kim, and the version which I grew up hearing about, one of the New Kids on the Block.