There's an episode of Frasier, where Niles pricks himself whilst fixing the seam on his trousers - he passes out a few times - it's quite possibly the funniest opening segment of a Frasier episode.
Any one know what it the episdoe is ?
Its episode 133 which is In season 6 of the show. The Episode is called Three Valentines and there is a review here;
http://www.geocities.com/goodnightseattle/ep133.htm
You are right..It's a really funny sequence that showcases David Hyde Pierce's excellent comedy acting and perfect timing.