Short videos on evolutionary biology
I saw this HHMI video today. It is called The Animated Life of A.R. Wallace, and it discusses the contributions that Alfred R. Wallace made to evolutionary theory. It is a little long for your stated time of 3-minutes. but it talks about how in fits of malaria he came up with his ideas on evolution.

HHMI also has a whole series of videos and modules on Evolution, though Wallace's came to mind as it showed his ambition and desire to solve the problem, even though he had not received formal training in the sciences.