MPU (mobile party unit). A core group of partiers who always party together, week after week, regardless. They MPU consists of only the most intense individuals who stay true to partying.
Joe: So the MPU rolled up to Gary's house last night.
Bill: Dayumm, those guys are hardcore
Joe: Fuck yeah they are, they left at noon the next day and had a box of bagel bites and Keystones for breakfast.