AVATAR is a Live Action Role Playing game organised by the Belgian LARP Federation.
All official documents concerning the world and the rules can be downloaded vie the official site: http://larp.be/avatar. Or more precisely here: http://www.larp.be/index.php?option=com_docman&task=cat_view&gid=53&Itemid=71. They are available in French, Dutch and sometimes in English.
There is also an extensive picture gallery: http://www.larp.be/photos/main.php
Asking questions and discussion are possible on the federation's forum: http://larp.be/forum