University of Chicago: Antonio Montalban and Yannet Interian's "Module on Puzzles"
Work on the problems on this webpage: liars and truth-tellers puzzles, the Rubik's cube, knots and graphs, and arithmetic and geometry.
Click http://web.archive.org/web/20160620151052/https://math.berkeley.edu/~antonio/MEC/mec.html link to open resource.