I'm going for the obscure one, and say There Goes the Groom.
At the very beginning Compo is getting ready to go out for the night, and is saying goodnight to his ferret. Clegg calls, and as they slam the front door shut it collapses. Brilliant little scene.
Then we get a good night shot of the...
Go on YouTube and type in 'Voice Wizard'.
This man is a genius at impresssions, he has recreated lost Hancock radio episodes by imitating Tony Hancock and the rest of the gang.
He can impersonate virtually anyone it seems, I wonder if he could Last of the Summer Wine.