Ron Bauer and Dick Zimmerman wrote a production called "The Presidential Production" that is exactly what you are looking for. It is inexpensive, easy to do, portable (basically it is a window shade!), and completely scripted. It is very funny, and amazing to boot. The idea is that a member of the audience (Usually a saleman for the company) is asked on stage. He is given a chart that unrolls (the window shade type device), and is asked some questions, the answers to which are all scripted and very funny. Each time he answers a question, the shade is unrolled revealing the next question. Next to each question is a box to enter the score for his answer. After the final question the shade is completely unrolled in front of the saleesman, so he is out of sight. The magician adds up his scores and says: "You got five points for each question, five questions, a total of twenty five points, a perfect score! With a score like that you should be the president of the company!" A voice comes from behind the shade and says: "I am the president of the company!" The shade is dropped and the salesman is gone, the president is there!
This looks great - let me say that the saleman is covered for less that 20 seconds, the change appears impossible. The five questions are very funny, as are the answers, and they are all business related so they make sense in the context of a sales or business meeting.
This appeared in a Genii magazine in the eighties, with everything you need to make it up, and a complete script. I believe Dick is on the cover...