@Jakob: There was one Christian heresy, early on, that involved hanging upside-down for 20 days to achieve purification. I've never been entirely certain that the author who mentioned it didn't slip it in as a joke...but I hope it's true.

Past that, my favorites would be the Arian and Nestorian heresies - really, we have them to thank for the Nicene Creed and the Council of Ephesus.
@Philologos: "Christ's incarnation through resurrection as a homeopathic remedy" - elucidate?
It should be noted that the heritors of the Nestorians repudiate the name and I believe the alleged doctrines of the Nestorians of old. The official preferred title is Church of the East, using the liturgy of Addi and Mari, to be distinguished from Greek and Slavic Eastern Orthodox and from the Syrian Orthodox - who also repudiate the name Jacobite and associated doctrines.