If you want to see a show while you're in town, try and grab some tickets at Boulder Theater in Central Boulder. Why not take a stroll along the riverfront and watch the sunset while you're here? It's also full of great shops and restaurants, so you can spend the afternoon having a wander. If you enjoy the show and want to see another, Fox Theater, Dairy Center for the Arts, and Upstart Crow Theatre Company are not far.
You can find out about the history of Boulder with a stop at Downtown Boulder Historic District. Check out the shops and top-notch restaurants in this walkable area.