One of the best games I ever played was 1480: The Age of Exploration -- a game that is no longer extant. Indeed, I suspect that the whole genre of similar games -- there were a handful -- is now extinct.
Each player in 1480, and there were about forty of them, played as the ruler of a country from Europe, the Middle East, or North Africa. The game began, as you might expect, in the year 1480 -- and was played in real time. That is to say, one real world year equalled one game year. Roles were extremely diverse in terms of power and capabilities -- thus, you could play an enormous military power like the Ottoman Empire, a huge trading and naval power like the Republic of Venice -- or, at the other end of the spectrum, a minor little state like the Palatinate of the Rhine (my first position, though later I became King of England).
There was certainly a military aspect to the game -- you commanded armies, cannon (each individually named and necessary to take cities), and galley fleets; but at least as important were the economic aspects, which was centered around the production and consumption of luxury goods (I imagine Streiber had been reading Braudel).
To make your moves in the game, you published a fanzine and sent it out to the other players. Thus, each month you'd get dozens of little fanzines -- each with one player's moves, and more often than not, royal announcements, statements of policy, rants against Papal iniquity, etc., etc. Diplomacy was extremely important, and some of us ran up huge phone bills calling and negotiating with the other players.
My proudest moment was when I, along with Ben Grossman, who played as the League of Hesse, put together a coalition of small German petty states, and marched our individually tiny (but collectively sizeable) armies on Vienna. Camped outside the city gates, we demanded that the Emperor lead us in war against the Ottomans, who were in the process of obliterating Hungary. The Emperor, who had previously indicated no desire to intervene in that war whatsoever, quickly decided that fighting the Ottomans was vastly preferable to having his capital sacked.
The game's creator was, yes, that Whitley Streiber -- I've never been able to figure out whether he went nuts, or laughed all the way to the bank, though I rather hope the latter. Whitley both served as a kind of gamemaster, adjudicating rules disputes and the like, and also played -- which may have been a mistake, as some of his rulings created contention among the players. I believe Whitley was trying to be impartial, but of course as a player his impartiality was inherently suspect.
There were a number of compelling aspects about the game. One was in essence, its quasi-massively multiplayer nature, in an era where games that permitted more than a handful of players were rare -- and, of course, the need to conduct diplomacy with most of the other players, so that unlike modern MMOs, the multiplayer aspect actually meant engagement with everyone else in the game. Another was the richness and detail of the research and world behind the game. But of course, a pure text game in a world of hypermedia seems archaic now -- as does a game with so slow a pace.
Yet it occurs to me that with the popularity of PHP-based "social network" games, a game something like 1480 might be feasible today. Part of the problem is that 40-or-so player limit; this is not a scaleable game, and could not support itself on the "free but upsell" basis of existing social network games. And, of course, so esoteric a subject would limit its appeal to a small niche audience. But it's worth thinking about how to solve such problems; certainly, social network games so far are mostly fairly brain-dead, and need to find new directions.
And it would be fun, of course.