A project started by Dave Grohl
in 1998, consisting of Dave himself playing most all the instuments with different vocalists he grew up listening to providing the... well, the vocals. The vocalists are, in order as they appear on the album,: Chronos (Venom), Max Cavalera (Soulfly, Sepultura), Lemmy Kilmeister (Motorhead), Mike Dean (Corrosion Of Conformity), Kurt Brecht (Dirty Rotten Imbeciles), Lee Dorrian (Napalm Death, Cathedreal), Wino (The Obsessed, Hidden Hand, Place Of Skulls), Tom G. Warrior (Celtic Frost), Snake (Voivod), Eric Wagner (Trouble), and King Diamond (Mercyful Fate). The Probot album was released in 2002, and has one video to it's name (Lemmy's track Shake Your Blood). It also has a hidden 12th song provided by King Diamond that starts about 3 minutes after Sweet Dreams. It absolutely rules my life, I don't know what I would do without Probot.
Go buy it. NOW!!! cause I said so