(This was originally posted as a reply to a question in 2010 NaNoWriMo)
Well, you have the famous Led Zeppelin mudshark + groupie story. Google that one yourself, I ain't telling.
Most of Almost Famous is based on real stories from the 70s, but most of the accidents were toned down for the film. [spoilers] Both the electrocution scene (happened to Stone the Crows, fatal in real life, not in the film) and the air plane trouble happened in teal life(Lynyrd Skynyrd lost three members to an air plane crash in '77). [/spoilers]
During the interviews several of the band members say things that are verbatim what 70s stars have said during interviews.
Airplanes are a source of trouble for musicians. So much so that you have a list over music fatalities here: http://listverse.com/2008/01/09/top-10-musician-plane-crash-deaths/. The song "American Pie" by Don McLean starts with the story of the trio on first place in that list.
Legends amongst those working in the business are maybe not so funny, but I have been told about the legendary Van Halen rider of '82 so many times (sometimes told with other famous bands of the time as the main characters, sometimes with red or green m&ms instead of brown) that it's something I feel needs mentioning. Full story here.
There are many legendary injuries, like the pyro blast James Hetfield got in the face in '92 that could have killed him or maimed him had it not been that his guitar was a solid body one. You also have the Great White's pyrom, which set fire to a club. A hundred people died, including their guitarist (http://en.wikipedia.org/wiki/The_Station_nightclub_fire). NME had a list over several less serious injuries here: http://www.nme.com/photos/rock-n-roll-injuries/124827/3/1.
You have the legendary Roger Waters spitting episode: http://www.angelfire.com/va/battersea/spit.html
And the time Leonard Cohen walked of the stage because he was "too depressed to play on". (Can't find anything about this, so that might just be a nasty rumour considering how Cohen is famous for being depressing.)
Anything Phil Spector (the man behind "the wall of sound") ever did, from threatening the Ramones at gunpoint, almost shooting John Lennon, threatening Leonard Cohen at gunpoint...
“He put his arm around my shoulder, pressed the muzzle into my neck and said, ‘Leonard, I love you.’ At which point I said: ‘I hope you really do, Phil.’”
That man was mad as a hatter and probably made more famous artists pray than any priest. There's even a list over his top ten moments.
You have the disappearance of Richey Edwards from the British band Manic Street Preachers in '94. He left his passport, parked his car by a bridge and was never seen again. Most of the people who knew him refuse to believe he killed himself, and his family told the press that they still believed he was alive when they declared him dead a few years ago, but needed to get the paperwork in order. The band still saves 1/4 of their earnings in case he returns.
For the more gory you have both Ozzie Osborne's bat eating incident (and his dove eating incident, and his "shooting all his dogs and hiding under the piano" incident)...
Twisted Sister's went to court to defend their songs from censorship (explicit lyrics, parental warning). The speech didn't help them win the case, but is pretty cool in its own right (calling Tipper Gore a pervert, amongst other things).
And while we're in court, Judas Priest who had to defend themselves from the accusation that their music made children kill themselves: http://www.bbc.co.uk/music/sevenages/events/heavy-metal/judas-priest-subliminal-message-suicide-trial/