I just got back from sixteen hours of board gaming. Sadly, eight of those (and an hour or more for the rules) were all one game: 1870. I almost shrieked when I saw the estimated playing time of four hours on the box; boy was I in for a surprise. That was almost certainly the most intense game I've ever played. Not only do you have to manage your own resources, but the resources of each company in which you are the majority stockholder. There's a whole stock market simulation game, coupled with a whole railroad building and management game, along with secret deals between corporations and lots of other little twists thrown in.
My feelings about the game were extremely mixed: I'll never play it again. Ever. You can do too many other things in nine hours to make it worthwhile. It's a really excellent game, though; things are perfectly balanced, there's no luck after the initial turn order is picked, and you have to plan out strategies for half an hour in advance or more. I have great respect for it. But, respect does not equate love, nor desire to play the game again.