What is English Country Dancing
A form of social dancing developed in England that was popular from Elizabethan times to the beginning of the nineteenth century. A modern revival began early in the twentieth centuries and continues to this day, in England, America, Canada, the Netherlands, and recently in Japan!
Dancing is done in sets of couples, in a wide variety of formations.
Here is a sample video:
More detailed information:
The English Country Dance mailing list (also includes a list of links)