In the making of YouTube videos in a mathematics context, a common approach is to rewrite a song that is already popular. Perhaps the reasoning is that the recognized music and plays on words will prove sufficient (i.e. be highly viewed).
For example, students and teachers of all levels of secondary mathematics perhaps might enjoy Mathmaticious, which is a fairly clever re-write of Fergie's Fergalicious. More than 1,894,000 views of Mathmaticious!
Fergie's song must be popular amongst mathematics students, given there are other less successful efforts (in my view) at parodies, e.g. Calculicious.
Again, as part of the resources for this next year, I am trying to suggest an on-line video(s) each month. Thus, if you have a favorite video (e.g. YouTube, TeacherTube, whatever....), please send the link to me (with your comments?) and I will try to include it and share it with others.
Source: First recommended by S.M. (WWU student)