there are several story telling festivals in the U.S.

perhaps you could grow your event into such a thing.

http://www.sierrastorytellingfestival.org/

http://www.lastorytellingfestival.com/

http://www.timpfest.org/

are you going to welcome others to tell stories?
perhaps you can include audio or video recordings...
will you be representing different cultures, or countries?
will you pick a theme ?
some of the most effective stories i have heard involve
either costume or a prop or an activity such as "cat's cradle"
(designs made with string, by manipulating with fingers)

this festival combines folk music and dance with storytelling
http://www.ctmsfolkmusic.org/festival/Solstice/default.asp

In the native american Hopi culture, storytelling is an important
and honored act...and there are many pottery figures which portray
the storyteller...always surrounded by children.
http://www.penfieldgallery.com/story.shtml
http://www.grandcanyonlodges.com/shop/product-view-0s-7c-69i.html

good luck...and let us know how it goes..