A conversation with Richard Lewis can go many directions. During a recent interview, the comedian touched upon, in no particular order: Jonathan Winters, Bill Clinton, Slash, MC5, Larry David and Sigourney Weaver, among others. But what seemed to be most on Lewis’ mind was the fact that he turned 64 earlier this summer. “When I hit the stage, every show is really important,” said Lewis, who performs at Synetic Theater in Crystal City this Friday and Saturday. “They’ve always been important. But now I’m not sure when I’ll come back to this venue, or if I will. It gets a little spooky for me when I gig now. I just don’t know how long I’ll be doing this, or how long I’ll be able to do it. Every gig is like Super Bowl time for me now, more than ever. My energy level is really through the roof now when I hit the stage.”