The highest density of Byrnes can be found in Ireland.
Weymouths live in Australia, Frantz is typically American.
And the Harrisons live in England.
...and after checking that, and your own name, and discovering that the Angels live in Spain, your curiosity takes over and you find out that Shit is a common family name in India, the Bummers live in Austria and Obama could be the president of Japan.
http://www.publicprofiler.org/worldnames/Default.aspx
Any other 'interesting' finds?