active Kansas City area mountain bike club. The website also includes information about Kansas City area mountain bike trails. Many of these trails are also great for trail running.
City's Adventure Racing Club
Kansas City has
many people currently active in the AR community. Use the below subscribe form to sign up for the club's Yahoo Group.
It's not terribly active (...won't spam your email box), but trust me people are there and listening. This is a great place to get started and to find out about Kansas City area races.