And for the best of both worlds: http://www.catb.org/jargon/html/koans.html

The first one's my favorite:

    A novice was trying to fix a broken Lisp machine by turning the power
    off and on.

    Knight, seeing what the student was doing, spoke sternly: “You cannot
    fix a machine by just power-cycling it with no understanding of what
    is going wrong.”

    Knight turned the machine off and on.

    The machine worked.