This always cracked me up:

The brand is not named after the famous St. Pauli neighbourhood in Hamburg, which is home to one of the world's largest entertainment and red light districts. Rather, the name comes from the former St. Paul's Friary [de] in Bremen, which was next to the original brewery established in 1857 by Lüder Rutenberg. There are currently three brands of beer brewed: St. Pauli Girl Lager, St. Pauli Girl Special Dark and St. Pauli Non-Alcoholic Malt Beverage. The beer is only produced for export and is not sold in Germany.