Chris Brown — Prison Schmizon … LET’S PARTY!!!

Chris Brown didn”t let the threat of 4 years in the big house get in the way of a big night out in Hollywood Monday … because Chris partied like a rap star at the Playboy Mansion.

Brown — whose probation was revoked Monday afternoon in the Rihanna beating case — mugs with 2 cute chicks at a charity event to celebrate the MLB All-Star game.  

Chris hung with Snoop Lion and L.A. Dodgers phenom Yasiel Puig (fast becoming a Hollywood party animal).

Playboy Mansion with the homies … every guy”s cure-all.