Liar Game. To quote GeeJoe on Reddit: "A detailed exploration of psychology and game theory. Throughout the tournament, the anonymous organisers introduce increasingly complex scenarios for the "contestants" to act out. The solutions are all discoverable if you want to think them through for yourself (though the optimal strategy is, after the first one or two, often incredibly non-obvious or counter-intuitive at first glance). Or you can just sit back and enjoy the protagonists solving it themselves." I rather enjoyed the character's personalities combined with the actual game-theory content; it seems to be in a way like a more serious version of what many people like about the series Death Note.