Preparing to Give a Funny Best Man Speech
Make some notes about how you know the groom and/or bride, wonderful things you want to say about them and particular amusing incidents that you remember. Work a bit on delivery in front of a mirror.
Don't try to be a stand up comedian - However, you can offer a tasteful joke related to weddings and then segue it specifically to your bride and groom. Or, you can retell a funny story involving you and the couple. You don't want to only address the groom or the bride too much - you want them to share in the attention.
If you're game, you can play a practical joke on the bride and groom (and everyone else) and then "fix" it during your speech. For example, if the bride or groom is a vegatarian, have someone from the wait staff hand you a piece of paper and then appear all flustered and make up a story about how someone in the kitchen mistakenly did something to the meal, like cooking the mushroom stroganoff with regular milk and sour cream, etc. By the end of the speech, of course, you fess up to the joke.
Laughter generated from amusing innuendos or a humorous turn of phrase will create a nice memory for the bride and groom. Remember being funny is OK but make sure what you say is in good taste and always keep a good light on the bride and groom and those at the wedding.
For more wedding speech suggestions, see Best Man Speeches and Wedding Speeches .