The Sword in the Stone (1963)

Arthur (aka Wart) is a young boy who aspires to be a knight's squire. On a hunting trip he falls in on Merlin, a powerful but amnesiac wizard who has plans for Wart beyond mere squiredom. He starts by trying to give Wart an education (whatever that is), believing that once one has an education, one can go anywhere. Needless to say, it doesn't quite work out that way.

Merlin, transformed into a squirrel, does a brief one ball juggling routine with an acorn, including spinning it on his finger.