(I voted for this!)
Okay, so I like where this is going, but I need to throw in a few ideas else I'd feel like I'm wasting my time having just read this thread (after all, you put a lot of work on this, and it seems you're wanting good feedback.) Let's start with games.
Mind you, these are suggestions--nothing else, nothing more.
1). Games should be designated in an arena zone; an audience zone is any place that is adjacent (and has visible access) to the arena--this means that you could set an audience zone one z-level higher. This doesn't preclude then the addition of multiple z-level buildings.
2). Games should have their parameters defined in the raws, allowing modders to generate their own fun new games; as well, on world creation, semi-random raws could be generated for games. The raws will contain things like teams, and players; you could specify a range, have a token for equal teams, or set teams at radically different numbers; items with interaction tokens; and goals. This would mean a simple game of soccer would look like:
[GAME:SOCCER]
[TEAMS:2][PLAYERS:2:10][EQUAL]
[ITEM:leather ball:1]
[PUSH:leather ball]
[INTO:goal]
[ITEM:stone block:4]
[SCORE:goal:leather ball:1]
[WIN_SCORE:10]
[ARENA:SOCCER]
[AREA:goal:2]
[ITEM:stone block:2]
[ITEM_PARAM:1:3]
[ITEM_LAYOUT:stone block:goal:stone block]
[GOAL_OPPOSITE_LONG]
[ARENA_SIZE]
What this code does is, when it's time to play soccer, two sets of two stone blocks are set on opposite sides of an arena zone (longwise), with a space in between them. The token 'push' means use the body to move the object (a ball) 'into' a predefined space, as defined in the arena, scoring 1 point. . You can then move it around (using distance parameters instead of simple [ITEM_OPPOSITE_LENGTH] use [DISTANCE:10], so the goals are always 10 squares away in the most convenient placement. Instead of playing 10 points, you could instead define [TIME:500] for 500 ticks, and use the token [WINNER_HIGHEST]. The problem is, there will have to be many permutations to the code to permit EVERY game that you can think of; such an idea should be implemented small, then more and more tags added in as the updates roll out.
Once the game ends, the dwarves pack up and clean up the arena. This allows you to run multiple games in one zone, instead of arduously having to build each arena for a specific game.
3). "Vermin games" (as oppposed to "large games" as I demonstrated above) could be done a lot smaller, because they require luck and possibly skill, and aren't so well defined in the RAWS. There wouldn't be a point to adding all the tokens in to make poker or bridge work, it would to be much work; same with jacks or chess or clue--this can be added in with required mats. The only problem is that playing them in adventure mode will get boring, unless each game has randomized "win" and "lose" tags that display whenever you lose.) A game of pool might then end up being a vermin game, instead of a big game.
As for arts (such as bone crafting), I think even idling dwarves might want to go and not just paint, but perhaps widdle on some wood for a while, making a few spare items on his free time--a handcrafted (perharps marked by a single grave accent on each side, ``, would have its value calculated differently. The subject `Launching of Orbs` would have a different cost if it was *`Painting of Launching of Orbs`*, versus an engraving of *Engraving of Launching of Orbs*. Same with `Handcrafted Statue of a Triangle`--they would also qualify differently to dwarves. An artist dwarf might get happy thoughts from `handcrafted` item, while an unartistic dwarf would only get happy thoughts from the manufactured sort.
That's all I can think of at this moment...