Public Speaking Tip: Use Humor
Use humor in presentations to make yourself more likable. Humor is a great rapport builder which knocks down audience resistance to your message. Make sure you space it throughout your presentation. You will subconsciously or consciously be tagged as trite by the audience members and out of touch if you tell a joke at the beginning and then forget humor for the rest of the presentation.
(Ref: Wake 'em Up Business Presentations Page 4)http://www.antion.com/wakebook.htm