Frank Wang is the author of a DVD lecture called Beauty and Mathematics. While I can't speak to the product itself, there are two videos on that page to which I wish to draw your attention.

First, there's the Birthday Paradox. Statistically speaking, in a gathering of 23 random people, there is a 50% chance that two people share the same birthday, which Professor Wang demonstrates.

Even more interesting to Grey Matters readers will be the Death-Defying Feat video. His life really isn't at stake, unless he screws it up. The feat itself is quite amazing, though. He asks someone to choose two 5-digit numbers, and to name them, but with the digits scrambled up (in other words, with the numbers not in the original order). The student is then asked to multiply the two chosen numbers together, and to give the answer scrambled up, with one digit missing. Despite the mixing of the numbers, even in the answer, Professor Wang is able to correctly give the missing digit!

No, the answer isn't given anywhere (except, I'd expect, on the DVD course), but I can tell you that the feat is much easier than it would appear to be. If you need hints to how it's done, you could either buy the DVD course, or read Harry Lorayne's new book, How to perform feats of Mathematical Wizardry.

Video Format:
QuickTime