This is the second most important part of your speech. An example that summarizes your entire argument well and can be used for transitions and the conclusion.
Lets look at the 'Greed is good' example again. I'll use Alexander the Great's decision to conquer the world as my intro/main example for this. We'll get into how to choose and refine examples in a moment (it's number 3 in importance). For now, just know that you need a good example here. I usually do the main example last for just this reason.
This example needs to encapsulate your interpretation, your argument, and your main two points, and it needs to do it all in 30 seconds. That's actually a little bit shorter than most examples. So it needs to be well chosen. This is your second priority. I do it last because then I can pick from all the examples I've come up with for the speech.
Think of this as your entire argument in example form. I'm saying that greed, irrational desire, is good (thesis) because it lets you ignore other people and drives you to success (argument). Alexander the great is an awesome example for this because he's not considered greedy, yet was. He was very greedy. I think the word usually used is heroic, or grand, but anybody quoted as saying 'Is it not worthy of tears that, when the number of worlds is infinite, we have not yet become lords of a single one?' is greeeedy. Greed for what, is the point.
Start your intro with a powerful sentence which clearly states what you're talking about, something like 'Alexander the Great was a greedy, greedy man.' Humor is good here but if it's not your thing just be clear. Make your entire point in the first sentence. Then elaborate; 'He wanted to take over the entire world and started out with nothing but a small army, a rebellious peninsula, and a pocket full of dreams.' Then, once you've elaborated a little bit, make your argument. 'Alexander's pocket full of greedy dreams, however, proved to be the key factor in his success; his greed led him to attempt what others said was impossible, and also led him to relentlessly continue until he achieved his goals.'
Mkay, three sentences. That's pretty good. Now you can throw in some filler for a sentence or two, make it funny if you can or play to your unique strengths, but also make it cogent. Talk about his greed, his attempts, his success, his crazy quotations and tendencies, whatever.
Finally, before introducing your quotation, introduce intrigue! Believe it or not, this is one of the most important parts of your speech, and also ridiculously easy. Just give people a reason to consider disagreeing with you. Something like 'But Alexander's greed led him to do such... interesting... things as burn the great city of Thebes to the ground, kill one of his generals for arguing with him, and pick up another wife on his travels.' See, now you're like Hm. Which sentence was his argument? Is he saying greed is good, or greed is bad?
This leads us into today's quotation, from the film Wall Street. You should see how that led into the quotation, and why it's worth thinking about. Then you go into your thesis and argument and preview and that's how your intro ends.
The main example is key for giving your audience something to hold on to, a common thread throughout your speech. You'll come back to it twice more in conventional, NFA impromptu, once when transitioning between your points and once in the conclusion. That's why it's important that it summarize your argument, the controversy, and the ideas in the thesis well. It's your audience's liferaft. Make it good.
Tomorrow we'll look at how to pick examples in general, and my favorite ways of outlining and remembering them.