Started in 2008, a yearly music festival sponsored by Rockstar energy drink that takes place in the summer. Started by Vans Warped Tour founded by Kevin Lyman and by John Reese (partner of Lyman on Taste of Chaos Tour).

Dominated by metal bands (mostly death metal) but will also have plain metal, heavy metal, and nu-metal. Most bands are todays metal (i.e. no Metallica, Iron Maiden, etc.)

Some bands that have appeared at Mayhem are Slayer, Korn, Lamb of God, All That Remains, Disturbed, Slipknot, Cannibal Corpse, 3 Inches of Blood and tons more.
Guy1: Are you going to Mayhem Fest this year?

Guy2: Hell yeah! Mayhem fucking rules!! Man, Ozzfest is looking dead now.
by RoboChickin July 19, 2010
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A large group of rapists wearing Disturbed basketball jerseys
Guy 1: Yo dude, you going to Mayhem Fest this Saturday?
Guy 2: Lol no, what do you think I am, a rapist!?!
by Jimmy "The H-Man" Rustle July 11, 2013
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