Behavior Incentives

• The Confutatio Pontificia, by Anonymous
• The Aeneid
• The Project Gutenberg eBook of Zen and the Art of the Internet, by Brendan P. Kehoe
• The Project Gutenberg eBook of The Marvelous Land Of Oz, by L. Frank Baum.
• The Tapestried Chamber, by Sir Walter Scott

Math Rewards

• The Rape of Lucrece
• The Project Gutenberg eBook of Common Sense, by Thomas Paine
• The Project Gutenberg eBook of William Gibson Interviewed, by Giuseppe Salza
• The Project Gutenberg eBook of On the Duty of Civil Disobedience, by Henry David Thoreau
• The Soul of Man, by Oscar Wilde

Airplanes

• The Amateur, by Richard Harding Davis
• The Aspern Papers
• The Project Gutenberg eBook of A Discourse on Method, by René Descartes
• The Rime of the Ancient Mariner, by Samuel Taylor Coleridge
• From London to Land's End