In this months
Spa magazine there's a great article on just this subject. The writer went to Azulik in Tulum and experienced a spa treatment that included a tamazcal (sweat lodge) ritual and cenote dip. She also went to Playa and stayed at La Tortuga and had treatments at Itza Spa. Then she took a tour (maybe through Altournative tours?) where she went to some little town about and hour inland and did another Tamazcal ritual with a Shaman and a night swim in a cenote that she described as something like she's never experienced...something magical. I was going to post a more detailed thread about it but I don't have the mag here with me. The Mayan believed the cenotes were the underworld and had magical powers both good and evil. I think the whole place is magical.