Summary: C, Smalltalk, Lisp, Erlang, Haskell, and Prolog. I know a little or a lot about all except Smalltalk (I've read lots about Smalltalk but never programmed anything in it)

I found this page again last weekend, it's easy for a math/cs nerd to blow a lot of time here...

Clay Shirky on the "cognitive surplus". Clay is an _amazing_ speaker.