Going to a Unitarian/Universalist church as a young teenager had an interesting effect on me.
The UUs as they often refer to themselves participate in yet another religion of Judeo-Christian origin. But, since they reject the trinity, they are definitely on the liberal side of such religions.
Looking through some of the ideas that have been ratified by the General Assembly (the big yearly UU gathering) one will find that they support legalization of marijuana, other drugs, gay marriage, etc.
A very progressive church indeed.