I have a tragic case of Iskconism in my larger family circle. One young man, who had a very high-paying job, married and after getting a son, suddenly got attracted to iskcon. As many people may know, iskcon is the brainchild of Bhaktivedanta, a Bengali, Gaudeeya vaishnavite. For them Krishna, and perhaps, even as important as krishna, Radha are the twin supreme godheads. There are no other godheads and all the rest of the larger hindu pantheon are either demigods or demons!
This young man was so keen on putting his (only) child in the iskcon school/nursery, that his wife ultimately went away with the child and now divorce proceedings are going on. The young man has become an iskcon sanyasi, but he is not ready even to look after his bedridden old mother (father died of mental shock after getting to know that his son was going down the iskcon drain!).
The gaudeeya is a branch spun out of vaishnava schizm. The Brahmavaivartha Purana is their most sacred scripture. It says that Radha along with krishna, her lover, is the Supreme godhead in the entire universe and krishna created vishnu, brahma and Siva. Curiously, Ganesha, son of Shiva and Parvathy gets one full canto of this purana, called Ganesha Khanda. Anyway, as some people firmly believe, Vyasa Maharshi himself composed/wrote this purana also, in Banga Desa, in order to educate the devout people (throughout bharatavarsha) in the correct moral ways of life!
Jayadeva's Ashtapadee describes this Radha-krishna relationship, which includes oral sex as also a scene in which Radha places her foot on krishna's head as part of their love-play. iskconites treasure all these stuff as the sure-shot way to final liberation. During Jayadeva's times it was more a tantric cult with unlimited and free-for-all sex as a method of enlightenment (and Osho caught upon this idea and propagated it, successfully.). The ruler of Kalinga proscribed Jayadeva and his work from his kingdom, because he felt Jayadeva was a threat to public morality.
But this kind of Radhe-krishna worship caught on still further north in Bengal, Brindavan, Mathura, etc., areas. The present Brindavan with its krishna, Radha temples and many widows, etc., is only a sad reminder of the erstwhile Radhe-krishna cult and widows trying to emulate the supreme Radha. In Bengal, this bhakti-madness went to the very extreme of devout men observing menstruation (of course, falsely) and the untouchability connected with it etc., in the hope that they had become one with Radha; thanks to the British, this nonsense was exterminated with an iron hand, but some isolated fringe-groups within the very lowest castes, who fled the British territory then, are reportedly continuing this madness even now.