Marshall: I can't do it. I can't run that far. I can't outrace anything. I... I can't... I can't get my wife pregnant!
[Maury Povich passes by]
Ted: Wait. Is that what this whole stupid running thing has been about?
Marshall: My body has been letting me down, and I just wanted to prove that it could still do something, but it can't.
Ted: Dude, you've been trying for two months, not two years. That's nothing.