Unlimited resources?
First a rather limited idea: Game room v1.0
Ok, table that fits 12 people comfortably, dms end has a mixerboard with stored music and sound effects plus a background switch. The background swith activates screens in the walls and roof which basically ar back projected screens unto which lights in differents color are directed. This makes it possible to simulate a changing environment, such as a forest, a starry sky etcetera, not too obtrusive, and certainly not enough to cause motion sickness in those that easily gets it.
The slightly more outlandish version (which came to me in a dream actually.)
DM sits on a raised podium with an array of buttons and levers on it, this controls the gaming field which is perhaps 10 yards by 20 yards and basically like a holodeck with some machinery. It's played using a mix of live events, live fights, exploration etcetera, but with the usual rules, some dice rolling and so on.
In the dream the opposite side of the playing filed held bleachers for an audience. The entire room was the size of a sitcom/tonight show studio.
Ok, time to go completely overboard:
Terraform the moon, make it one big fantasyworld with some inbuilt safety to prevent deaths. Perhaps a large scale of the theme parks in the movie West World.
And while we're terraforming things, let's do Mars to for a larger playground, perhaps with different continents being different genres.