Oscar Isaac should get an Oscar nomination for the Coens’ “Inside Llewyn Davis.” Even if he doesn’t, his career has kicked into the big time. It’s about time. Here he is with Jimmy Fallon from last night’s show playing Katy Perry’s “Roar” as a folk song. Cool cool cool. The movie just opened, and goes wide next week. This Saturday Oscar and a cast of folk superstars have a great concert film on Showtime. Don’t miss it.