Pilar Rioja is in town, performing her amazing flamenco here as she has for over thirty-five years at the Gramercy Theater on E27th Street. The wondrous thing is she is seventy-five years young. Here's inspiration for anyone who feels age should get in the way of their passion. If you didn't stand up and at least clap your hands while she danced start polishing that rocking chair, baby. Now, where did I put my castanets?