In 1965, ABC aired a Saturday morning cartoon based on The Beatles. It was the first animated series to feature real, living people. Of all 39 episodes, only 8 are known to be available on YouTube. All episodes were available at one point, but almost all of them have been taken down by UMG_MK due to copyright troubles.
Update: All the Episodes aren't missing, the full episodes can be found on Kisscartoon and Dailymotion.
Dailymotion  (Note: Scroll and you'l found it)