Because they're convinced I am a cat hoarder.
LONG SHOT: What I really hoard
I've read the majority of these. And feel kinda guilty about having not read all of them.
I hit amazon.com every few months and browse for improv books (my recs get cluttered with various Star Wars books I have no interest in—as fascinating as the Jedi Reader series sounds, I've been reading at a third grade level since I was five, thank you). It's amazing how the numbers have picked up in the last few years...you used to have the big three: Something Wonderful Right Away, Improvisation for the Theater and Impro. There were a few game books, but mostly in the elementary or lame categories. Then Truth In Comedy opened the floodgates (I so don't feel like linking everything. Just go here.)
Now it's hard to keep up.
(The ones up on top are various leadership and other-fleeting-hobby books.)