Couple of helps towards humor.
First off, Jane Espenson's blog -- specifically Sunday, May 16th: The Dangling Kitten (how Glee correctly told a joke); Monday, May 3rd, Not Loving It (how McDonald's ruined a joke); and Sunday April18th, Go With the Flow (how Progressive saved an old joke).
Smart lady, smart advice on humor. (She also worked on Battlestar Galactica, Firefly, Buffy, Angel and Gilmore Girls -- I think I may have seen one of those shows...)
Then wander over to Jon Acuff's article at Relevant, where he talks about the difference between satire and mockery. (As a side benefit that Relevant may never have imagined, you get insight as to why the Daily Show really works when it works, and why when it doesn't, it really doesn't.)
Just my "I'll get you a kitty" type thoughts,