A colleague's site mentioned this excellent resource from Deutsche Welle (German Broadcasting). It reads Langsam gesprochene Nachrichten which means Slowly Spoken Reports. It's a 10-minute daily newscast delivered in an even cadence using perfect Hochdeutsch (High German) pronunciation which is found primarily in the north of the country. It's slow by German standards, but sounds relatively speedy to an American ear.
I studied German for seven years in high school and college, and have spent just a tiny bit of time in German-speaking climes, such as Frankfurt, Bad Bergzabern (find that on a map), and Basel. The last is a town in a German-speaking canton of Switzerland where they speak Swiss German, a set of many similar but distinct dialects that are almost incomprehensible and unlearnable even to High German speakers. (The Swiss speak and write perfect High German as a lingua franca, and are pleasant to converse in it because they don't care about it as their mother tongue.)
Even the Swiss German name for Swiss German can twist the tongue: Schwyzertütsch. The dialects vary so much that two adjacent towns might use different words and pronunciation, while traveling 50 or 100 miles puts you into foreign territory.
The same was true about Italian spoken in Ticino/Tessin, the Italian-speaking canton in Switzerland. They speak dialects that can vary literally over a few miles. And let's not even get started on Romansh.