I just got hooked up with a new site which features low cost to free adventure activities in the Denver metro and mountain areas. Chump Change Adventures (http://www.ChumpChangeAdventures.com) organizes adventures by audience (children, teens, families, couples) as well as by type of adventure. In addition to outdoor activities, it has listings for classes, seasonal, and business opportunities. I especially enjoyed the calendar of events which included a complete listing of REI classes for the beginner through experienced outdoor enthusiast. Sharon Otto, the founder of Chump Change Adventures hopes to expand her site to other cities around the country.
Good luck Sharon!