Gary Dourdan -- BEST PLEA BARGAIN EVER!!!

Gary Dourdan smashed in to 2 parked cars at 3:30 AM on June 13, 2010 ... he was arrested for possession of OxyContin ... yet today, Gary skated in court with a $100 fine.

Dourdan pled no contest to 1 count of disturbing the peace -- an infraction -- and in return the OxyContin possession charge was dismissed. Prosecutors also agreed to dismiss a separate charge of drug paraphernalia possession.

We're told the reason the L.A. City Attorney dropped the drug charge is because Gary completed 20 hours of Narcotics Anonymous.