I am not sure just how many are aware, but a good portion of pre 1974 television and movies are no longer copyright protected. Up until 1974 renewing copyrights was not common because it appears that it was still unsure if this media would catch on or how to go about such a thing. Anyway, we have all see the massive release of old shows on DVD, From the Lucy Show to the Beverly Hillbillies. Well there is a complete site for such and they also hold one of the largest databases of 100% free stock footage, much provided by Getty.
It is amazing what is no longer copyright protected
"It's a Wonderful Life"
"The Boy in the Plastic Bubble"
A ton more, it also means you can use clips.
Here is the site
Read the details of each clip, some portions may contain a song that is still protected.