I don't know if you have done it already, but here is a list of things you can do at your thesis defense.
http://people.msoe.edu/~taylor/humor/defense.htm
don't put ideas into my head!
i now have to try and forget the following, cos i'm soooooooo fucking tempted:
74. Use a Greek Chorus to highlight important points.
118. Use both sides of your overhead transparencies.
120. Do your entire defense operatically.
132. Bring a microphone. Point it at the questioner, talk-show style.
brilliant!