Gerard Butler arrived without gal pal Madalina Ghenea at a screening and party for his new film “Olympus Has Fallen,” and was “surrounded by leggy lovelies,” said a spy. Also at the Cinema Society bash sponsored by Roger Dubuis on Monday night were Angela Bassett, Norman Reedus, Debbie Harry and Mira Sorvino, who at first wasn’t recognized by bouncers at the Darby after-party. Aaron Eckhart popped up at a different Union Square screening, and we hear stars will make surprise appearances at further sneak peeks.