In the epic running scene where Gimli, Aragorn & Legolas are tracking down the Uruk-hai who nabbed Merry and Pippen, if you watch closely, about half-way through as the camera pans left (I think, could have been right) you can see Legolas stumble over some rocks before quickly continuing running as though nothing happened. I know this may sound trivial at first but after noticing it the first time, I always see it and can't help but laugh at the irony.