Fallon was fumbling over his words but he specifically mentioned Potter, and presumably Forbidden Journey. Now we have Peterson involved seemingly, and looking at their website, this is my guess (all speculation of course):
Facade will be 30 Rock, and the rest of the street will have a full, Manhattan makeover. "Aftermath" obviously is an NBC store. You enter into Rockefeller underneath the marquee, and the former outdoor queue will now be enclosed as you wind thru a faux tour of the building. Flat screens above feature Fallon talking about the building, setting up that you're going to see a taping of the show. This winds you to where Twister has the first double doors. Except this time, a TM is lining guests up into three rows of fifty while we grab some 3D glasses. The double doors declare this the entrance to Studio 6B. This is the pre-show, and Fallon is excited to start the show, but says that they're trying something new and experimental today. The doors open, and this time its a set of three ramps that take us into the studio, and the audience is three tiers, right in front of us is a recreation of Fallon's NYC studio.
Suddenly we notice that the seats are remarkably similar to FJ, and that this HUGE bench is all on one giant kuka arm behind us, but that hasn't been fully revealed. The TMs tell us to lower our OSTRs and put on our glasses (whatever they theme them to be probably a silly joke), and the show begins with the Roots coming out, and Fallon starting his show. He cracks a couple jokes, and then for repeat factor, a different celebrity each time will pop out to challenge Fallon to a race around NYC. Fallon asks if the audience can join them, and the celeb says yes (and doesn't appear in the ride film).
Suddenly, the arms start shifting and the studio magically drops and the IMAX screen becomes the focus as we fly above 30 Rock and then plunge into the streets. Cue ride film. The kukas will have the ability to give more flight and movement sensation, and Jimmy makes cameo apperances. We crash back into Jimmy's studio which magically reappears. There's a quick joke by Jimmy and he wishes us goodbye, the OSTRs lift while the Roots, still in musion, play out as we leave into the NBC store.
One problem is that the capacity will probably be pretty harsh since there's only room for one theater (thanks Rockit), I'd say closer to 1000 or less since I think the experience will probably be five minutes long at least. If they can manage to recreate the Rockefellar skating rink (leave that miracle up to UC) for the holidays, the entire thing could be really worth it.