Mr. Boring is best described as boring. He has many boring tales about his boring life and makes boring lecture videos about boring things like tieing your shoe or eating a sandwich. Mr. Boring is about as boring as boring can possibly get. Mr. Boring isn't a major character, so there isn't much to say about him other than the fact that he's boring and has the most boring lifestyle possible.
Oh, and he's a teacher at Joeschool