mmouser:

Find some trails near you and check them out! Some amazing opportunities. Try http://www.trails.com/ and immerse yourself in your surroundings. For those of you in Colorado check out http://www.go-colorado.com/Hiking/.

 This looks like a great resource. The trails on the map show up with little icons to indicate whether they are hiking, biking, running, etc. trails. I could definitely use some new ideas for places to run in my area!