Pretty sure I've done this before, but what is your favourite ever comedy sketch?

Only rule is that it must be from a sketch-based comedy show. None of your sitcom bollocks.

For me a couple spring to mind:

- Two Ronnies mastermind sketch. An oldie, yes, but I remember being in tears the first time I watched this http://www.youtube.com/watch?v=y0C59pI_ypQ

- The Scientist sketch from Big Train. Again might not have repeat value but was howling with laughter at this. that guys laugh :') http://www.youtube.com/watch?v=TOAPUcxpBOk

Now...you go!