A bit of advice -- don't tell jokes in a deadpan. They'll think you're serious. I've gotten into assloads of trouble this way.
I love jokes told in deadpan!!! They're hilarious. Even if I don't get it at first (admittedly I'm kinda slow sometimes), once you explain then I think they're really funny. Hap, you can tell me those kinds of jokes anytime.
I was fired from two jobs for telling a joke. Bureaucrats don't have a sense of humor.
The first thing to do if you're trying to develop a sense of humor is to not take yourself seriously. Also, it's much advisable to trivialize real happenings that most people are too uptight to make fun of.