Don't know about all time, but I thoroughly enjoyed a very clever short film called Treacle made by Peter Chelsom, the director of Hear My Song and Funny Bones. It's a black and white British short about three generations: grandfather, father and son. Father and son live under the shadow of grandfather, who once had an enormous music hall hit but since he sold the rights for nearly nothing, his descendants got naff all out of it. The father is a failed Northern seaside entertainer, played by Freddie (Parrot Face) Davies, who spends a lot of the film just looking at his grim surroundings in silence. The climax of the film is when the grandson exorcises the demons with a brilliant punk version of the song, in which even the old folk in the audience bop along. Probably hard to find this film, but it's highly recommended. Shame that so many small classics such as this slip through the cracks, because some ******* at UCI cinemas think showing them might cut into our popcorn spending time.