Theatre Aspen, an Aspen summer mainstay in Rio Grande Park, officially opens its summer season tonight with the rollicking comedy with music, "Mama Mia." Theatre Aspen has become one of the must-see cultural events of the summer, and its shows are superbly presented and acted in the beautiful Hurst Theatre in Rio Grande Park. For lovers of live theater, the intimacy of the theater-going experience is unique. The other shows being presented this summer are "Buyer and Cellar" and "Dear Edwina." Tickets and summer calendar at theatreaspen.org.