What kinds of things do you like to do? Are you an active outdoor person or more of a museum person? Coors Field is a great place to catch a game, driving to the parking lot near the summit of Mount Evans (14,000+ feet) and a light hike to the top is terrific fun and that's a good time of year to do it.

More details about the kinds of things you like will help a LOT, because there are many varied things to do in and around Denver.