Thanks to Boing Boing making the site melt down with popularity, creating a new #1 post of all time, I see that A Theory of Fun also climbed up the charts, hitting #1 in the abstruse category of
Books > Subjects > Computers & Internet > Games & Strategy Guides > Programming. Woo hoo!
This does make it the #5 best selling game book, though, behind the strategy guides and atlases for Sims 2, EQ2, and WoW.