Ethical Culture movement

The Ethical Culture movement is a non-theistic movement which seeks to promote ethics independently of theology or woo. In the 18th Century the Conway Hall Ethical Society was established, making it the oldest such existing establishment in the world. It was founded by Felix Adler, an American former rabbi-in-training in the 19th century who offered only one sermon before realizing that his synagogue wouldn't take too kindly to all that "atheist" talk.

Modeled somewhat after traditional independent church/synagogue structures with leaders, the Ethical Culture movement had an upshoot in growth for a few decades from the 1880s to 1920s, with Ethical Societies being established in North America and Europe. It declined in popularity soon afterward, but the British movement was the incubator of what became known as the British Humanist Association. Ethical Societies still continue to persist to this day, with many being concentrated in New York; the current federation of Ethical Societies in the United States is known as the American Ethical Union, which was a founding organization of the International Humanist and Ethical Union.

Specifics
The Ethical Culture movement does not explicitly refer to itself as an "atheist" or even "humanist" movement, and it only concentrates on theology-agnostic ethics, or divorcing the theistic association between being a theist and being a good person. In this way, the Ethical Culture movement is very often compared with the UUs in not caring about your beliefs or lack thereof.

Nevertheless, numerous members identify as atheists, agnostics or humanists, and individuals such as Sam Harris have spoken at Ethical Society events.