I have once heard "The Old Rugged Cross" done as pub entertainment, in a very rough bar in a hard-core Protestant part of Glasgow. The guy doing it had a terrible toupee and sang to the accompaniment of his own cheesy electric organ. The only other item I can remember from his set was a rugby-club version of "Abdul the Bul-Bul Emir". Quality stuff.

I have been involved in campaigns that got infiltrated by Scientologists. They're as hard to get rid of as herpes and about as much fun.