This one hasn't come up despite the presence of UCLA on the net.  I'm
led to the sad conclusion that the tradition has died.

In the mid '70s, just before it was overrun by fanatic Dungeons \&
Dragons (tm) players, the UCLA Computer Club was host to a long series
of "glitter traps."  Example: joke subject sits at a desk, pulls out a
drawer.  A string runs from the back of the drawer, up the wall, into
the false ceiling, over to a spot directly over the subject's head,
where it triggers the trap: a mousetrap whose action snaps a card away
from its position covering a funnel, releasing a handful of glitter,
which flows down the funnel, through its spout, through a hole in the
ceiling acoustic tile, onto the subject.  It was wonderful to watch: a
muffled snapping noise, a quiet "chuff," and the slow, glittery descent
of a cloud of brightly colored dust, to settle over the head and
shoulders of a club member who by now has assumed an expression of
appreciative resignation.

Another, more short-lived ploy was to suspend a wooden horseshoe by a
string from the ceiling in the corridor, such that the horseshow
dangles a couple of inches above the top of an upright broom.  Most
conventional brooms will stand on their straws with a little coaxing.
We attached a sign labeling the horseshow "wood magnet."  Quite a few
people took it at face value.