It's unusual to find a good book that speaks to instructional technologists and people outside the field, and I've been fortunate enough to find two such books this year.
On Intelligence, by Jeff Hawkins and Sandra Blakeslee, is a fascinating exploration of the biological basis of intelligence that has very practical implications for designining learning experiences. Hawkins posits (and supports with evidence) how the brain learns -- how new experiences are recognized and remembered, and how those experiences become ingrained as knowledge (and reflex) with repeated exposure. While saying "practice makes perfect" is old-hat, seeing how the brain makes and manages predictions can only help us design more effective, and acurate, forms of practice.
A Theory of Fun For Game Design by Ralph Koster tackles the questions of fun and engagement in a fun and engaging way (even my 13-year-old son wants to read it), and ties the "fun" in games to what games have to teach us. Yes, Koster says the "fun" in games comes from learning, and the learning is helped by the "fun". (This is also not news: "recent neuroscience research is revealing the amygdala/hippocampus' (the brain's emotional system) important influence on learning and memory" [Martinez, 2001].)
These are both thought-provoking reads that would be great to take on a cross-country flight and then loan to your friends.