Bill Graham was probably the biggest rock concert promoter ever, and during his life, he kept concert paraphernalia and memorabilia from all of the shows he promoted. He amassed a huge collection of concert posters, t-shirts, concert tickets and much much more. A lot of it is now being sold on Wolfgangsvault.com. One of the main draws to the site though, (aside from the concert memorabilia) are the hundreds of concerts from some of the biggest names in rock, streaming for free.
Yesterday, a lawsuit was brought forward by members of the Grateful Dead, Led Zeppelin, and Santana.
They allege that Sagan (the owner of the site) is violating their copyrights, trademarks and publicity rights by selling originals and copies of memorabilia and by streaming to the public tapes of rock concerts recorded by Graham. For years, the Grateful Dead have allowed taping and trading of their concerts, and these shows are streaming for free. I think it makes the Dead look pretty bad by trying to sue now.
My suggestion, listen to the concerts while you still have a chance.