The Frasassi caves: http://en.wikipedia.org/wiki/Frasassi_Caves , http://www.frasassi.com/SitoWeb/Iframe/En/home.aspx?Piatta=Microsoft#
are very interesting. A tour is organized during the congress. .
Several delegates have had a lifelong dream to visit Venice
This would be a full day trip
and need to take place before or after the conference on your own.