At the CHI 98 conference, there were several uses and presentations of ZUIs.
Of particular interest, Ben Shneiderman gave the opening plenary talk, and used Pad++ for the first half of the presentation (to about 2,500 conference attendees)! We've made the files he used available. It will load into Pad++ Version 0.9 on Unix or WindowsNT. It is available in different compressed formats (.tar.gz for unix and .zip for windows). The files will be extracted into a directory called 'shneiderman-chi98'. Then, just start Pad++ and open the file 'shneiderman-chi98/shneiderman-chi98.pad'
Note: This file will not load into Pad++ running on Windows95. Unfortunately, there is a bug with the Windows95 version and it crashes.