Joshua Dyal said:
Where's the

when you need it? No, I mean the calendar doesn't really enhance the fun of the game for most players. Roleplaying is a hobby, not a school assignment. If my players don't think learning how a new calendar works is fun, I'm hardly about to tell them they need to, even if as a DM I think it's fun to create one. (Incidently, I'm not entirely sure I do; I prefer calendars to have ease of use rather than silly fantasy flavor.)
I mean, here's another example. I'm a bit of an amateur linguist. I'd like to really complicate the rules for linguistics and language aquisition and use. Frankly, though, I doubt any of my players would appreciate or enjoy it if I did; quite likely, in fact, they'd find the whole thing frustrating and annoying. So I find a middle ground; I do something that balances ease of use with a bit of flavor, and in general everybody's happy.
In my experience calendars are the same way. Even Tolkien converted his Middle-earth calendar into Gregorian.
I'll stand by what I said, and elaborate (ahem, more detail! No groans from the audience!) on why I have that opinion.
Perhaps I'm not like most players, because I
do find world-setting details like calendars to be fun. As I said, I'm a setting-whore. Fully half the fun for me as a player is learning about and playing in worlds different than our own, and by that I mean all the details — geography, culture, history, philosophy, etc. As a DM, half the fun for me is creating or modifying such detail. I'm the sort of person who will want to know all the names of the streets on a city map, or want to know all the details of a country's armed forces, or sit down with a map and try to figure out latitudes and longitudes of places using map projection formulae, or compile a list of every single noble family mentioned in a kingdom... or figuring out details of astronomy and cosmology from calendars! Go ahead, bring on calendars with different month names and based on two moons and a slightly different year length! I'm the sort of person who
would enjoy your rules for lingusitics and language acquisition. Now, as a DM, if I get all this fun out of creating or presenting setting details as an integral part of the adventure, and I go through all the work of doing it, then if I have a group of players none of which who care about it or get fun out of experiencing it — or at least acknowledge and appreciate it — then they're urinating in my breakfast cereal. Not everybody in the group has to share what I get fun out of, but at least some do or gaming's just no fun to me.
To me, an RPG is at least as much an intellectual exercise in worldbuilding as it is a vehicle for storytelling — that's what makes it fun for me. Storytelling by itself bores me. A generic-type adventure which is solely focused on the events of the adventure itself in which no setting details were involved and nothing beyond the core rulebooks were needed — an adventure that's just characters going on a quest for gadget X without any real broader context or setting in which the adventure takes place and the charcters can interact with beyond the narrow confines of the adventure — would bore me to tears.
I have the same preference for fiction (written or film) in general. This love of setting and worldbuilding detail is why I like science fiction and technothrillers as well as fantasy, and why conventional mainstream stories that are solely about people and events they go through (and could easily be real people in the real world) bore me to tears. When I watch Star Trek, or Babylon 5, I get as much fun out of what details are revealed of the greater universe as I do the actual drama of the story. If I watch an episode that gives lots of little details about history, culture technology or other worlds, then to me it's a great episode even if the plot was mediocre or even poor. Likewise, a decent story that is entirely character-based and doesn't reveal anything about the greater world or universe about them (in other words, the sci-fi or fantasy setting is pointless and the same story and dialogue could just as easily happen in the real world) is going to get a "sucks" rating from me. It takes an
exceptionally outstanding story to survive a lack of setting detail in my mind. What can I say, I'm a setting-whore!

[And yes, as you might gather the uber-Storyteller "gamers" who put Story above all else annoy me too.]
Roleplaying is just a hobby, not a school assignment? Not to me! If you're not going to exercise your brain, give it a workout, what's the point? People who say "lighten up; it's just a game" irritate me. If it's worth doing, it's worth taking seriously. If it's not worth taking seriously, then it's not worth doing at all. When I'm at work I take my work seriously, and when I play I play seriously. Anything else is a slacker mentality and no way to live life. That's the way I like to approach RPG's and the attention to world detail therein!
If I had a group of players none of which appreciated or enjoyed a richly detailed setting and all of which whom would find dealing with such detail frustrating and annoying, then I'd just rather not DM them at all. I'd rather not play than play in a game with little to no attention to the greater world setting around the characters. Go ahead and roll your eyes if you must, but I stand by my criticism and general disregard for people who don't appreciate setting detail or are annoyed by it when I go through the effort of presenting it. If you enjoy your detailed work in languages, I'd at least think you'd understand my perspective even if you don't necessarily agree.
So bring on the alternative calendars for the gaming world! They're fun! Players who can't be bothered to deal with them are lightweights!