I love how all of these Rankin/Bass classics from the 60s and 70s get classic old Hollywood and Broadway stars to provide voice talents; lends a certain seriousness to the occasion.  Here we have Fred Astaire narrating and singing a couple of songs in this 1970 stop-motion retelling of the origins of Santa Claus.  Fred's a mailman delivering letters from kids to Santa, and he stops to answer some questions in the charming opening credits sequence which quotes most of the musical themes from the 50 minute TV special, first broadcast when I was 5.  Santa was an orphan left on the doorstep of the mean Burgermeister Meisterburger (I still love that name) in Sombretown (ok that's a little corny) with merely the word "Claus" on a chain around his neck.  The Burgermeister is a mean old dude and doesn't want him, and through mysterious, fortuitous circumstances he ends up with the Kringle elves in the Mountains of the Whispering Winds.  He grows up learning to make toys, befriends all the animals of the forest, and goes back to Sombretown to give toys to the kids - but is met by the Burgermeister's opposition.  Along the way the reasons for the red suit, the flying reindeer, the belly laugh, etc, are all explained, with the voices of kids breaking into Astaire's narration at times to ask him to verify that this was, in fact, how it happened.  Kinda cool even for this adult.