Researchers at the University of Alberta have concluded that hand gestures improves memory and the ability for people to choose the correct word.

Furthermore, another study is mentioned here, regarding student/teacher evaluations. Apparently, professors who make more hand gestures receive higher evaluations. (Thanks to Angus Fletcher for first mentioning this. If anyone can find additional information (the researchers were (Williams and Ceci), it would be welcomed here. Thanks. -- TK)

This all leads me to believe that some groups of people have an advantage in this memory game. On that note, About.com has listed around twenty Italian hand gestures and their meanings. And, there are also five important Buddist hand gestures on the Government of Tibet's site.

Finally, this last strange site lists international rude hand gestures that do not include the middle finger. Unfortunately, no illustrations or diagrams. Interesting reading though.