Modern Square Dancing is a social activity where 8 people form a square with 2 people on each side, then they dance a series of movements as "called" by the square dance caller.  It is a healthy, recreational, fun activity.  It is often said that square dancing is "Friendship Set to Music".  Dancing is done to all eras of music, from classical through to fairly recent numbers, Show & Broadway, Elvis, Country, and many more.