The blog Things That Don't Suck provides a very funny rundown of this movie (loads of spoilers!)
that involves, well.. an evil cult, the devil and rain. But it's the Devil's Rain!
And if that isn't enticing enough, how about a cast that includes William Shatner, Eddie Albert, Ida Lupino, John Travolta, Keenan Wynn and Ernest Borgnine as Satan!
And the technical advisor was none other than notorious High Priest of the Church of Satan,
As a special treat, until YouTube removes it, here's the whole movie!
WARNING! This movie is seriously weird and once you've seen it, you can't unsee it! Enter at your own risk.