I wasn't a kid when most of you were kids. But first thing that popped in my head was The Incredible Mr. Limpet. I mean, I'm not quite old enough to have seen it first run and I don't remember where I saw it, but I often thought back and wondered, Did I really see that or did I dream it?, because it's not overly popular. There was talk years ago of a remake with Jim Carey but never happened. I think it would have been interesting.
My other favs are old Walt Disney Productions live actions of the '60s that I never hear anyone talking about: The Ugly Dachshund, The Horse in the Gray Flannel Suit, The Love Bug, The Absent Minded Professor, The Computer Wore Tennis Shoes, The Shaggy Dog