Monty Python has a few precursors to the "random famous people mixed together compting" format, although not in the rap fight format:
Video 3.
Philosophers' Football Match by Monty Python (1972)
. Source. If you can understand the jokes, your philosophy level is pretty good. Like more than zero. Wiki page: en.wikipedia.org/wiki/The_Philosophers%27_Football_Match. Ciro loves how that page currently uses a standard footbal match template to describe the match!