Ok, I'll go first:
How many of us are also excited by rotating their pen around the thumb,
I don't know if I'd use the term "excited", but I do this annoying behavior. It's a nervious thing. I'm a very nervious person. Twirling a pen or a balisong is just an outlet for some of that energy.
handling a nunchaku at high speed
Never have.
learning fancy ways to draw a sword
Depends on what you mean by "fancy"?
drawing a gravity knife in one fast wrist move,
Gravity knives, no, but conventional folders, yes, Aside from the combative applications of this, "flicking" my folder is just a nervous outlet for me.
manipulating kama like Jimmy Pham,
Sorry to show my ignorance, but I have no idea what a kama is or who Jimmy Pham is.
throwing their Glock

behind the shoulder and retrieve it in the other hand
My only Glock was a gift from a girl friend and I don't want to dammage it. Some people keep a flower pressed in a book; I've got a Glock. Besides, I'd be scared of a Glock accidentally discharging. But, A P7, well, that I certainly do practice handling, drawing, and firing frequently.
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Chuck
Balisongs -- because it don't mean a thing if it ain't got that swing!
http://www.balisongcollector.com