If you’re an aficionado of smart comedy, the place to be on March 31 was off-Broadway’s Barrow Street Theatre for opening night of Mike Birbiglia’s My Girlfriend’s Boyfriend. A who’s who of NYC comedians and comic writers turned out to cheer one of their own, as Birbiglia debuted his latest theatrical solo show. After sharing comic tales of his lifelong struggles in the romance department, the normally dressed-down star put on a coat and tie and happily posed with his famous guests.