Breaking Derek

You'll see the odd mention of some of his friends "breaking Derek." That doesn't mean that we occasionally attacked him and caused him serious bodily harm. What it means is that occasionally, we would surround him with such vast depths of hilarity, or he would simply be in such a humor-susceptible mood, that he would start laughing and be unable to stop.

Here's Andrew Petrarca on the origin of the term "to break someone".

A couple of little tidbits that just occurred to me...  One is the origin of
the use of the term "to break someone" to mean making them laugh
uncontrollably.  As I recall, I was in F13 along with Derek and one or two
others, and someone said something that made Derek lose it.  I scolded the
offender with a line like "Now look what you've done, you've broken Derek. 
Now we're going to have to get a new one."  We then proceeded to discuss
the matter as if we'd just dameged a piece of furniture or some such.  This
didn't help Derek any in his struggle to stop laughing...

As the years went on, we who were close to him refined the breaking of Derek to an art form. We discovered and then developed the uses of break triggers, and learned early on that such triggers could be used on an already-broken Derek to sustain the breakage further. Eventually he would turn purple and stop laughing for lack of air; however, his lungs and all would still be trying to laugh, so he'd be making these odd whooping sounds and sucking air whenever he could sneak it. Eventually he would recover, sucking in a huge, heaving breath; at that point it was accepted practice to hurl another trigger at him and rebreak him. High on the oxygen debt, he would be an easy target.