I'm probably far from the first APer to discover this, but I just noticed that Garmin Connect has a "heat-map" - showing where all the Garmin tracks in an area line up - a good way to find other runners/cyclists when in a new city...
http://www.gpswatchreviewhq.com/garmin-connect-add... has a good story on this
To play with it, go here,
http://connect.garmin.com/course/1908050 zoom slowly out to state level (after which the heat maps turn off) and find your area. :)