Generation Grunge is growing up, or rather, getting old. Recently it was announced that Nirvana's Nevermind is turning 20 this September, and now Pearl Jam is celebrating the big 2-0 with a Cameron Crowe documentary called Pearl Jam Twenty (they're actually turning 21—their first show, under the band name Mookie Blaylock, was October 22nd, 1990 at the Off Ramp Club in Seattle). It will be released in December, and here's what to expect on your journey back in time:

Pearl Jam Twenty chronicles the years leading up to the band’s formation, the chaos that ensued soon-after their rise to megastardom, their step back from center stage, and the creation of a trusted circle that would surround them... The film is carved from over 1,200 hours of rarely-seen and never-before seen footage spanning the band’s career.

The "part concert film, part intimate insider-hang" even features a cameo from David Lynch. Check it out, and remember: growing old is a state of mind. (And MTV just turned 30.)

Other things that recently turned 20:

• Temple of the Dog's "Hunger Strike" (21 years old!)
  
• Fugazi's "Waiting Room" (23 years old!)
  
• Milli Vanilli's Grammy. (21 years ago!)
  
• The introduction of MTV's Unplugged in January of 1990. (21 years ago!)
  
• Aerosmith's appearance on SNL's Wayne's World, singing the theme song. (20 years old!)
  
• Twin Peaks's premiere on television. (21 years ago!)