The Bytes Brothers
http://www.gamebooks.org/show_series.php?id=1171
Sort of a cross between Encyclopedia Brown and Micro Adventure, each volume in this series contains several short mysteries. The user must read carefully and run very simple BASIC computer programs in order to guess the solutions.
Amherst Magazine Winter 2004: Enigma Machine
http://www.amherst.edu/magazine/issues/04winter/extra/enigma.html
Looks like a massively redundant self-trepanning machine to me.