Falls City is definately a cool place. Lots of progessive stunts - you can go as big as you want or just cruise. The local riders put in many hours building and maintaining these trails, mostly during the week. Check out Santiambicycle.com and their message board for rides and trail maintenance. Santiam Bicycle is in Salem (about 15 minutes from Monmouth, and is a cool place to pick up hardcore parts and hang out.