I thought I have seen all possible multi-touch installations đ but here is a new one: Ubice installation.
Jonna and her group at NRC in Finland have built a multi-touch wall made from ice (frozen water – they seem to have plenty of it up there).
Even though it is on youtube (http://www.youtube.com/watch?v=bbtrI6GjBsk) we still hope to see a paper on this project – do the user study before it melts đ
The Interactive Tabletops and Surfaces 2010 conference is this year in Germany in November 2010: http://www.its2010.org/