According to the BBC, some experts say that having sexual intercourse is a good way to help prepare for a speech!
Now, call me a cynic, but I am not sure about that! Although I can imagine score of Uni students reading this today and thinking 'Oh, brilliant. I don't need to make notes on Friday's presentation/tutorial! I will just go out clubbing/spend the evening with my girlfriend/boyfriend', and as Dr Peter Bull says, "You are probably better off thinking about what you are going to say, and preparing thoroughly, rather than having sex the previous night."
Besides which, my sex life is nonexistent. In fact I will probably shock everyone right now and declare that I am a virgin! I don't see why I should be ashamed of that, and I am actually saying it to make the point that I am usually confident when making public speeches and therefore doubt that sex is crucial to making a succesful speech at all. I'm slightly nervous perhaps (about making speeches that is..), but confident. And I am sure I am not the only one.
That said, the next time I see someone striding up to a podium with a big grin on their face, I will wonder. And if they flunk their speech I will know ;).