When did Grey's 'Jump the Shark'? It really went off the deep end when Izzie starting seeing dead people. And talking to them. And having sex with them. But I'm going to be bold and call the "jump moment" even earlier. This might be a mere correlation and not a cause, but this show has been a stank mess ever since the end of the 3rd season when Burke left...

http://www.sidereel.com/posts/10657-news-top-10-shows-that-jumped-the-shark-part-2-featured

http://fresnobeehive.com/archives/upload/2007/01/iwashington.jpg