might sound odd, but one thing that I found helps is howling, after a few drinks down the park, I thought "why not?" and it gives you this buzz, try it and see what I mean. Best you're not around people though at the time, they might think you're crazy/going to eat them.
-Also, working out, I love putting on some Iron Maiden, Ensiferum or whatever and just doing a cross country run, never fails to cheer me up.
-Going out to the woods too, I've always had this love of nature since a kid, I could spend so much time in the forest, you wouldn't believe.
-Concerts, going to see a band with friends, jumping in the pit, I love it!