Since many believe exercise is the best method but hard to execute. I've recently started recording class lectures and read aloud any hand out readings and recorded them in mp3 format. Then I put them all in my iphone and started walking for a long time while listening to these. For me this works, at least for now, hopefully this becomes a habit. Even if you are not a student, you can listen to an audio self help book on depression while walking/running. Just an idea.