What do you do when you feel yourself falling back into depression?

i have never been clinically depressed, but when I feel a funk coming on I go do something outside. The sun and the fresh air does wonders for one's soul. 

Know that the night can not last forever and the day will come again. ☺

I think of that person who thinks he's a dragon---makes me realize nothing could be as bad as that, so I immediately realize I have nothing to be depressed about.