This article is from the soc.history.medieval FAQ, by Stephan Schulz email@example.com with numerous contributions by others.
The Society for Creative Anachronism is an international
organization interested in the research and recreation of the
Middle Ages and Renaissance. Most (but not all) of the people
involved in the SCA are amateurs who are interested in one or
more areas or topics of the Middle Ages. At a SCA event you
can see many people wearing clothing from different periods of
time (most between 600 and 1600 A.D.) doing different
activities. Activities can include armoured fighting,
fencing, heraldry, spinning, dancing, cooking, etc. (that
list could go on forever). However, because of the long time
period, and wide geographic range, most SCA events are not
accurate recreations of any one time or place.
The SCA does "not" insist that people dress or act exactly as
someone from the Middle Ages would, they just encourage it.
Thus many Scadians prefer to focus on the "current middle ages"
or the fun they have on the weekends without doing any serious
research. Other Scadians take the recreation aspect very
seriously and can become quite knowledgeable on certain
subjects. Some Scadians have difficulties separating historic
research and experience from the reenactment. This sometimes leads
to frictions in discussions with more serious-minded historians.
If you would like to learn more about the group you should
read the newsgroup rec.org.sca (also called "The Rialto" among
Scadians). People there can tell you how to get in contact
with the Scadians nearest you. There also is a WWW page for
the SCA listed in section 3.3.