Surely the best comedy sketch of all time to be set on a tube train. Ronnie Barker and Ronnie Corbett engage in smalltalk based almost entirely on the names of tube stations. Some of the references are dated, but there's no denying the brilliance of the writing and delivery.
Bonus point if you can name the station at which Corbett alights.
With thanks to Shirley Farrant Anstey in the Londonist Roundel Ramblings Facebook group for reminding us of this sketch, which was written by Kit Galer.