|Brent Spiner and Michael Dorn are generally considered to be the chief
jokers on the set of TNG. A common joke that they played on other
and each other was to break up what's supposed to be a serious
scene by trying
to make the other actor laugh. They would usually succeed,
except that it rarely
worked the other way around with Brent, which was
extremely frustrating to
those who were trying to get back at him.
Well, one day Brent went too far with Michael. In a scene in the episode
"Contagion", Worf was supposed to carry a seriously damaged Data
the bridge into the turbolift. To do so, Michael had to hoist Brent
over his shoulder and carry him like a 100+ lb sack of flour. While he
was on Michael's shoulder,
Brent tried to make him laugh by making strange
gurgling sounds in his throat. Klingons aren't supposed to laugh. After
having to reshoot the scene several
times because of Brent's antics, Michael
decided he'd had enough.
During the final take Michael marched across the
set with Brent. When he
reached the turbolift, he turned and slammed Brent's
head into the doorjam.
The expression on Brent's face never changed, and
that part of the scene can
be seen in the episode.
I don't know for sure if Brent has told this story at cons or not. But
of what happened was published in an issue of Starlog's TNG
a few years ago.