The group calls itself the "True Russian Orthodox Church". Members are waiting for the end of the world, which they are expecting to happen next May.The problem is that this group also includes four small children. But the cult leader did not join them (yes, he was indeed the smart one).
They say they have enough food and water to last out the winter, as well as large quantities of petrol.
The group was founded by a former engineer, Pyotr Kuznetsov, who had fallen out with the Russian Orthodox Church.Read the full story here. And while at it, here is a brief description of the classic text, When Prophecy Fails, by Leon Festinger about a social and psychological study of a doomsday cult and here is wiki-description of his theory of Cognitive Dissonance.
He is thought to have ordered his followers into the cave but did not join them. He is now in custody and is undergoing psychiatric examinations.