Best Man Speech

Hello! I am the best man of my sister's wedding. That's right, my sister and best friend are getting hitched. My wife is also the maid of honor. Unlike most best men I am going to know half of the guests so that is definilty an advantage for my speech. Given the circumstances I feel there is alot of oppertunity to make a great speech. He was also my best man as well. Any help to make this speech as funny and great as possible would be fantastic! Also wondering if there may be a way to tie in my wifes maid of honor speech or do it together in a funny way? Thanks!