I think this effect with one's phone number has been discussed in this forum before. But here's a website where you can do the mathematical "trick" yourself using your own phone number. Thought some people might like to see this!

Click here: http://www.flowgo.com/funpages/view.cfm/2069

Tried it myself, I agree it was a bit long winded. The ending wasn't really a mind blower as I'd already put my phone number in twice. So it didn't really blow my socks off. Theres a similar style trick called "guess the age" which I use. Its quicker and dosent invove as much information from the spectator as the named.

Adz

I seen this before, I have one that is much much better. Although like this, the one I use is not really a trick, but it is still cool though