Next month, O.G. indie label Matador Records celebrates its 21st birthday with a three-day Las Vegas blowout that the folks behind the label have dubbed their Lost Weekend. In addition to the festival, Matador announced today that it will celebrate its birthday with a massive six-CD box set called Matador at 21, which chronicles the entire history of the label.

Matador at 21 includes five CDs of remastered tracks from throughout the label's history, and one that consists of live recordings from the label's 1999 10th anniversary shows in New York. That means previously unreleased live tracks from Pavement, Cat Power, Mogwai, and Bardo Pond. Along with the music, the set includes an 85-page book that documents the label's history, and 36 custom Matador poker chips. They're really running with this Vegas thing! All this comes in a foil-stamped, linen-bound box.

Over at the Matablog, you can find photos of the box, as well as the tracklist. It's worth noting that the Matador folks didn't just include tracks from all the historically important bands in their catalog. So alongside Pavement and Liz Phair and Belle and Sebastian and Guided By Voices, you'll find Dustdevils and Unsane and 18th Dye and Arsonists and other stuff that you might've completely forgotten about.

On the same day that the box set comes out, Matador will also release a double LP featuring all the songs on the box's fifth disc, Matador Today. That one includes songs released on the label since 2008.

Proceeds from the box set will go to three charities chosen by Matador's owners: Chicago's Jane Addams Hull House Association, New York's Ali Forney Center, and the Heart Institute at Children's Hospital Los Angeles. All the bands included have also agreed to donate their royalties to those organizations.

In other Matador anniversary news, the Matablog has filled in more details about the Las Vegas festival, which takes place at the Palms Resort and Casino October 1-3. Liz Phair, the Clean, Times New Viking, Perfume Genius, and Esben & the Witch have been added to the bill, and MCs for the three days include Pavement's Bob Nastanovich, Jeff Jensen, and Scharpling & Wurster. Click over here for the full schedule, which also includes Belle and Sebastian, Pavement, Spoon, Superchunk, Sonic Youth, Yo La Tengo, Cat Power, and, of course, the reunited Guided by Voices.