I am a successful lecturer in physics for popular audiences. The real entertainment gimmick is the excitement, drama and mystery of the subject matter. People love to learn something, they are 'entertained' enormously by being allowed to understand a little bit of something they never understood before. One must have faith in the subject and in people's interest in it.
Perfectly Reasonable Deviations from the Beaten Track: The Letters of Richard P. Feynman (ed. Basic Books, 2006) - ISBN: 9780465023714