Congrats, dude!
I agree that funny stories are a good idea. The Class Speaker at my H.S. graduation was a very good friend of mine, and I remember him trying to write something that wouldn't be cliche. Since he knew that the valedictorian and student body president would both speak first, he decided to go wacky so that everyone wouldn't be bored by the time finished.
First, he had a member of the school board take his picture with the graduating class from on stage. That got everyone excited, and he then performed a song he wrote that talked about his fear of kindergarden, as well as poked fun at the many trends we'd experienced (ie, Pogs, Napoleon Dynamite, Power Rangers, Tamagotchi, Pokemon, Chuck Norris (an alumni of our HS), etc...), and it was fun to have that sort of "boy, we were stupid" moment.
Anyhow, all that to say that the humor is needed. Those speeches are way too boring to sit through otherwise.