Well, it's an applet containing some sort of video file.
1) Browse the source for the URL to the jar: jars/UWTransp.jar
2) add that to the page path URL: http://viscog.beckman.uiuc.edu/grafs/demos/jars/UWTransp.jar
3) Download jar and rename to zip
4) Open zip and extract the biggest file
5) Now you just need to figure out how to play it
edit: apparently the stream is cinepak (ew!) but I can't figure out the container format; vlc won't play it and it will play anything it supports even if it has the wrong extension
I think it would be easier to just download it than to try to watch it offline without downloading it...
Seriously: If executing the jar offline doesn't work - try the appletviewer command line tool (its included at least in the JDK, and IIRC in the JRE as well)