Do it again.
Absolutely, I would love to do it again. (Hand them your card and say:) I am gald you enjoyed my promotional entertainment, just let me know when you would like to book a performance and you'll see that one and much more. I do have to put food on the table and this is how I make my living. If your a student in school and being bothered by this give them a choice.
1. I can do it again but that's gonna cost ya. (The object here is to get them to ask you "how much?") Price: Well usually I charge $100.00 but for you it's half price.
2. If you don't have any money I can give you a shot at wining a crisp hundred dollar bill. (Option to see "There is a sucker born every minute" aka "Bank Night") If they take you up on this make sure they know part of the deal is if they don't pick the right envelope they cannot ask you to see any more magic. (Substitute any impossible challange here)
Yet another idea:
Show him a Charlier cut and say "If you want to learn how I did it so bad that you have to see it again, first you got to learn the basics. Learn that first (Charlier cut). When you can do this get back with me and I'll show you what you want to see again."
Or just tell them about a website where he can down load it like this one.