Can anyone name religious/spiritual groups in the USA that has many adepts? Large Reiki & Meditation centres?

Question

I'm looking for religious or non religious groups of people, in large scales, to analyze beliefs and summarise what is available for human beings in the USA.
Centres that do meditation, centres that do Reiki or any other type of Healing, religious groups that are "different" or special in their teachings, or beliefs.
Christians, Buddhists, etc, all do, the importance is that it has lots of adepts, maybe large scale events too.

Thanks all

Answer 1

There are a series of schools on the east coast, with many very competent practitioners that do energy work healing, including Reiki and other forms. You might get some volunteers through there.

http://www.dovestar.edu