Here's an interesting DNA tidbit. Many of us may be descendants of supposed mythical Irish king dating back to the 5th century.

http://news.nationalgeographic.com/news/2006/01/0120_060120_irish_men.html

That, of course, came from a link where I was reading about The Genographic Project, which aims to test at least 100,000 of us in order to create a database of genetic markers and trace the common human ancestry back to Africa. Sounds interesting, but paying $100 to be part of a study seems a bit much.