Tzolk’in is probably the best game I’ve ever seen in terms of how its mechanics fit its theme, with the Mayan calendar represented by an actual friggin’ moving clock/calendar right in the middle of the game board.  It’s a worker placement game with the added dimension of time, and that clock moves to advance the game but also increase the rewards that workers get for going after resources, all keeping with the theme of the Mayan calendar.  It’s not an easy game to follow and understand, with stiff penalties for failing to collect enough food, and the learning curve is fairly steep, so it can be a tough game to get into in that way.  There are many strategic pathways that have to be balanced with blocking your competitors, making every game a little different, even with the goals being largely the same.  It’s a deeper, more strategic games than most of what we play, but very satisfying if that’s what you’re looking for.