Woz even showed up to play it:
Woz showing up was the icing on the cake, and it was definitely one of the highlights of my college career.
Awesome to hear from someone who got to play it!
Pointless post is pointless.
They had to break in to the Rose Bowl stadium, design and build special boards to take over the scoreboard lights, and break back in to install the boards. The control of the board during the halftime break in the Rose Bowl game was done by RF link. This was in 1984, when hardware was much more finicky and expensive.
They even made the first few compromised banners subtle enough that the crowd kept going with it until the finale where they wrote "CALTECH," an unmistakable prank.
A more detailed story is here: http://today.caltech.edu/today/story-display?story_id=11464
I'm assuming there must be some central computer controlling the lights, either than or they attached something to / modified each light switch?