This is too funny!
The Best Man Speech Generator by Fire Fly Events is a hilarious Mad-Libs type online game that will generate a hilarious best man speech for you. You enter the bride and grooms names, and choose a few adjectives, nouns and verbs, and voila! A Best Man Speech.
Here's one for our best man:
I met Dustin when we were 16. Right away, I knew he was a tall kid and the perfect friend for me. He was always a hit with the ladies even at the young age of 16. I remember his best line was "For toes like yours I would play the biggest bicycle. Then along came Christie and everything changed. It takes a sassy girl to tame the dog that is Dustin. I remember they met at Mammoth Lakes and within the space of 27 shots he was wearing her skirt and she had slept all over his boat. Ladies and gentlemen I ask you to raise your glasses for Christie and Dustin. May they live absently ever after and have athletic babies.
If you need help deciding whether or not to have your best man or maid of honor deliver a speech, see Wedding Traditions You Can Do Without from Two Ring Studios' Blog.
If you want to go through with it, but need help, check out the Oratory Labratory, a writing company that will help you write a speech. Also check out Best Man speech dos and don'ts at "The Faux Man Speech" on the Wedding Bee.