I have a VHS tape of my cousins telling stories at a family reunion. The images on the tape were beyond my technical powers to save. The audio, however, was not too bad after a bit of tinkering. So, I snatched an audio track on which my cousin describes a family Christmas party, and added it to the video of a 1954 family Christmas party.
Another great soundtrack idea is to describe the images and scenes yourself, or to have a family member tell a story about what is happening on the video. In this way, the people in the video are identified and the event explained--much like labeling photographs.