Just yesterday, news broke that the UFC had signed one of MMA's most colorful personalities, Jason "Mayhem" Miller to a new contract.  The UFC wasted no time in booking him a fight and today, announced that he'll face Aaron Simpson in a middleweight bout in July at UFC 132:

"Crafty veteran and colorful personality Jason "Mayhem" Miller has verbally agreed to make his UFC return against powerful wrestler Aaron "A-Train" Simpson in a middleweight matchup July 2 in Las Vegas," said UFC President Dana White.

Jason "Mayhem" Miller (24-7)
Win Kazushi Sakuraba (submission - arm triangle choke) - DREAM 16
Win Tim Stout (TKO) - Strikeforce: Nasvhille
Loss Jake Shields (unanimous decision) - Strikeforce: Fedor vs. Rogers

Aaron "A-Train" Simpson (8-2)
Win Mario Miranda (unanimous decision) - UFN 24
Loss Mark Munoz (unanimous decision) - UFC 123
Loss Chris Leben (TKO) - TUF 11 Finale