Dominic O'Brien is a memory expert primarily known for winning the World Memory Championships 8 times. In this video (embedding disabled by request of submitter), he is given a list of 51 items by representatives from Guinness World Records, and is able to recall them, all while blindfolded!

His much-sought-after book, How To Develop A Perfect Memory, is available as an e-book from Lybrary.com.

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There have been numerous versions of the song American Pie, rewritten to be about Pi instead. The one I've seen go the furthest in terms of Pi digits, though, is Alex C. Thompson's version. A few viewings, and you'll know Pi to 30 digits!

If you're more ambitious, you can try this page which will help you sing it up to 191 digits! The music from this page comes from Hard n Phirm's Pi video, which is also available on Google Video and MySpace.

Video Formats:
Google Video
MySpace
YouTube

Richard Wiseman, in an appearance at The Amazing Meeting 4 (TAM4), creates a magic square, starting even before the number is named by someone in the audience!

If you would like to see more videos of magic square performances, check out Jon Stetson, Scott Xavier and me.

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This geometric appearance of a graph paper square uses the same basic principle as the Winston Freer Tile Puzzle, to which I linked earlier.

If these puzzles have you really stumped, you can find some great explanations and discussions of them by starting at the A Faulty Dissection (Java required) article and demonstration, over on the Cut The Knot site.

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Easy Mental Multiplication Trick - video powered by Metacafe

Here's an interesting and easy mental multiplication trick that involves nothing more than drawing lines!

Update (11/17/06): It's now also available on YouTube.

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MetaCafe
YouTube

This has to be one of the most amazing memory feats ever featured on Grey Matters Videos! “Thrond”, in less than 60 seconds, recites all the books of the Bible (both the Old and New Testaments), all the books in the Book of Mormon, all 50 US States, the alphabet in reverse, and all 43 United States Presidents from memory!

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“littlegoot” is a rarity. Like the recently-featured “Claire”, she's one of the few female Pi memorizers I've ever run across. “Littlegoot” is able to recite an astounding 100 digits from memory!

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YouTube

The Simply Outrageous Math video, which is also available on Google Video, is a short tutorial on various techniques to make some formerly complex mathematical problems easy enough to do in your head. While there are some techniques you'll recognize from the recent entry on Vedic math, there are plenty of new ones, as well.

Video Formats:
Google Video
YouTube

“Claire”, in response to Nick Blunt's “I Eat Math” video, shows off her knowledge of Pi by reciting 30 digits from memory!

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YouTube

No, the above presentation isn't technically a video. It's a presentation from SlideShare. What YouTube is to videos, SlideShare is to PowerPoint and OpenOffice presentations. Yes, Mac users can create presentations as well, using Keynote, or the Mac versions of the above packages.

This particular presentation teaches you how to square numbers ending in 5 in your head, and then how to use the same technique to mentally multiply numbers that are equidistant from the multiples of 5. To step through the presentation, simply use the two middle arrow keys to step back and forth through the presentation at your own pace.

If you like this mental math technique, you can also learn to do instant subtraction, multiply by 11 through 19, and divide by 9 in your head, too!

Video Format:
SlideShare