I was a member of an enthusiastic friends-and-family gaming group through the early and middle 1980s. We spent a good chunk of that time on Diplomacy, then moved to modified Diplomacy on custom maps (my first wife worked for USGS Map Sales, and so we had good maps to work with in creating our own Diplomacy maps), and from there we graduated to Nomic.
If you think Diplomacy is long and exhausting, wait till you get a load of Nomic with a bunch of enthusiastic players.
> In the words of Nomic's author, Peter Suber: "Nomic is a game in which changing the rules is a move. In that respect it differs from almost every other game. The primary activity of Nomic is proposing changes in the rules, debating the wisdom of changing them in that way, voting on the changes, deciding what can and cannot be done afterwards, and doing it. Even this core of the game, of course, can be changed."
That’s the one. An intelligent and enthusiastic group of players can extend it indefinitely. It’s all lawyering and deal making, even more than Diplomacy, it can continue for hours and hours, and you dare not leave the room for a second, lest all your carefully worked out dealmaking be washed away in an instant.
If you think Diplomacy is long and exhausting, wait till you get a load of Nomic with a bunch of enthusiastic players.