*grin* I always forget that, but then I started with 'Echoes' and wandered around all over the place before watching episodes in order. My all-time favourite (since I'm not doing the meme) is still:

Rodney: It's a brisk walk.
John: And by 'brisk' you mean 'far'
Rodney: And by 'walk' I mean 'run'

That and Elizabeth's face makes me fall off my chair, every time :)