Riot in Rhythm (1950)

Popeye's nephews practice their music, swinging out at the end. He puts them to bed with a perfunctory story; they say their prayers, finishing by blessing "all the nice people that come to see their pictures." But they're not ready to sleep, so they sneak down to their instruments. Popeye confiscates the instruments (even the piano) so he can get some sleep. The tots quickly realize that common objects in their bedroom can be used as musical instruments and they start swinging out on everything in sight. Popeye can't catch them in the act; they are always asleep when he looks in, even through the window or floorboards. He pulls his bed outside the iris-out, but they follow and he runs down the aisle of the theatre.