I'm a big fan of the 23andMe service (23andMe.com) and they just release a new feature that analyzes your DNA and tells you what kind of population your DNA is most common with. This is what it reads:
Ancestry Composition tells you what percent of your DNA comes from each of 22 populations worldwide. The analysis includes DNA you received from all of your ancestors, on both sides of your family. The results reflect where your ancestors lived 500 years ago, before ocean-crossing ships and airplanes came on the scene.
Here is how my chromosomes look like from the world. I find all this data and discovery about your roots and the science of YOU something truly magical: