Here's a link to a superb Version of the Hummer's Mathematical 3 Card Monte:
Hummer's effect was 'making the rounds' awhile back, so, I thought this page/info might be of interest.
Note: This is just one of eight effects described on the site. There are links to the other 7 effects on the page; Good brainfood (if you're hungry for such aquired tastes.)
FYI: This info/site is from the "American Mathematical Society" (& the link came from a long lost DME reference... I found it in my email box as I was doing some web-email-housecleaning.)
Hope someone finds this info useful...
(or am I the only one geeky enough to enjoy this?)