This is a great place to take in the views of Boulder up close! There is parking right at the "trailhead" and tons of hikes easy and hard to explore. If you're looking to site see around Boulder, this is a must stop.
Pearl Street Mall is Boulder's downtown, and features a ton of shopping and restaurants. The mall has several blocks of pedestrian only access, and is sure to have something for everyone. Try Sherpa's for some amazing Nepalese food, The Post for fried chicken, Sushi Katsu for fish, or the Avanti food hall for a tons of options and amazing views of the flatirons (tip: take the elevator to the top floor).
The University of Colorado is one of the most gorgeous campuses in the country. Maybe take a stroll around campus!