There was real-life drama at the Oscars when kooky Sean Young was arrested for slapping a security guard in front of the academy’s Governors Ball on Sunday night. The actress — known for starring in “Blade Runner” and “Ace Ventura: Pet Detective” — has a bizarre history of getting bounced from Hollywood bashes. This time, Young says she was at the party entrance to take pictures with guests for her Facebook page. She was spotted posing with Angelina Jolie, Brad Pitt and Sandra Bullock. Young admitted to slapping the guard, reports said, but only after he’d grabbed her. The fracas led to a “citizen’s arrest” before cops took Young into custody. KCBS-TV reported she was booked on misdemeanor battery charges and posted $20,000 bail before being released at about 3 a.m. Yesterday Young said her arrest was unwarranted and demanded an apology from the academy. In 2006, she got in hot water for trying to crash Vanity Fair’s Oscar party and was tossed from the DGA Awards in 2008 for heckling.