When I was growing up in Buffalo, on Sunday many radio stations changed their format for the day, and played nothing but polka music. Even to this day, several radio stations continue the Sunday polka tradition, if only for a few hours.
Meanwhile, in Cleveland, on Sunday some radio stations play polkas and oompa-like German and Eastern European ethnic music during certain blocks of time throughout the day. A station might play a couple hours of Polish polkas, then a couple hours of Czech oompa music, then Slovenian oompoa music, German oompa music, and so on.
What are the origins of the many Sunday polka shows? Are they common in other cities? What about outside of the Great Lakes region? Why Sunday?