More ways to take yourself less seriously...
7. Listen to less earnest folk music, whiny Emo music and angry country or rap, all of which take themselves too seriously. Listen to a little Cheap Trick, The Format, The Beastie Boys, Louden Wainwright III, Jimmy Buffett, Eminem or Ben Folds (I recommend this song or watch it here- explicit lyric warning).
8. Read McSweeny's, Landover Baptist, The Door, Graph Jam, The Onion, Stuff White People Like, or Veto Corleone... anything satirical (and not just the stuff you agree with. Find stuff that confronts your biases).
9. Laugh when people mock you, especially when you are being to serious. Mockery is good for us. Seek out things that actively mock things you like or believe. Watch it until you can laugh at yourself.
10. Watch 30 Rock and see how well the self serious fare, especially Jack, Tracy and Jenna.
11. Get a dog.