Literal videos. This is when happens when someone's got WAAAYYY too much time on their hands. They use the tune of a real song, watch the video, and make up words to go along with what's ACTUALLY happening in the video. Which, if you think of it, makes a lot of sense, because a lot of music videos seem to have NOTHING in common with the song that's being sung. Anyway, there are several examples of this type of video (worth looking up: Meatloaf's "I Would Do Anything for Love (but I Won't Do That)"), but this one is my absolute favorite:
Bonnie Tyler "Total Eclipse of the Heart"