I have the Blu Ray, and I noticed in the Season 1 episode "Next Door Indians" as soon as the opening credits began, I could hear someone cough and clear their throat. Very weird, as it wasn't heard in any other episodes.
For those of you who have the Blu Ray, go check and see if you hear what I heard.

hhehe I wonder if that can be heard in all versions of that episode?? (VHS,etc)