What was the Grey's Anatomy episode?

It was sometime after season 2 and before season 6. I wanted to rewatch it because it was hilarious. The funniest part was when George was trying to save a dummy machine's life that was being operated by Chief Webber and he was voicing over, saying funny things for the dummy. Hahn was also angry because she found out Izzie stole her patient's heart for Denny. Please help!!!