The best way to get excited about lecture material is to learn something new about it. Here is a sampling of great authors who never fail to stimulate me, no matter how many times I read them:
• Howard Ensign Evans, Life on a LittleKnown Planet (Dutton 1968) Before I lecture on sexual selection, I read the chapter on fireflies called "In Defense of Magic."
• Stephen Jay Gould I read Gould's articles in Natural History magazine to prepare for talking about evolution.
• Natalie Angier, Natural Obsessions (Houghton Mifflin, 1988) This account of research in the fast lane at M.I.T. is the perfect stimulus for teaching about oncogenes.