With rumors of a Nirvana boxed set and/or Greatest Hits CD surfacing, there are questions as to who "owns" the music of Kurt Cobain. The Rolling Stone article tells of master tapes found in Krist Novoselic's basement, one of which includes a pretty cool 1994 unreleased recording, "You Know You're Right."  However, the dispute between Novoselic, Dave Grohl, and Courtney Love continues, so grab the MP3 while you can.
Update: As I feared, the link to the MP3 is now broken. You'll just have to wait for the CD, visit your favorite p2p application (*cough*Kazaa Lite*cough*), or beg me to e-mail it to you ;-).