U.S. swimming champ Ricky Berens' suit split down the backside just before he stepped up to the starting block. There was no time to change, so he went ahead with the race. Here are some pictures of him. You'll be seeing some crack if you click these links, so be forewarned. He has a very nice crack though!
Towle Road
Huffington Post
It also happened to Italian swimmer Flavia Zoccari.