I ran a lunchtime SICP reading group at my last job wherein we read a section or two at a time and someone (usually me) would illustrate the concepts by walking through our own Java code base (a big industrial ad server). It helped that we were already using a bunch of functional programming idioms, and that we had a few little compilers in the code to begin with, but viewing all that agile-developed code through such a pure academic lens remains one of the more professionally rewarding exercises I've yet had.

Even though I'm still mostly a mouth-breathing Java programmer; at work anyway.