For our LUG event I made diorama displaying mix of Inka, Maya and Aztec cultures and one of the first visitors from old world.
More photos can be seen at http://www.brickshelf.com/cgi-bin/gallery.cgi?f=533203
What you could not seen from pictures: diorama is interactive with visitors. There are six functions operated by vistors by 6 buttons mounted on a pole in front of diorama. 3 buttons lid lights in 3 temples. 1 button start flashing red eyes in two small statues left and right of middle temple. 1 button starts rotating calendar on top of right temple and 1 button made kanu came out of the watterfall and back in.
There was additinal function in plan (big sail ship to circle arround the sea on old blue train rails). Problem was that PFtrain motor I put into the ship is not powerfull enough to gently start driving 1,5kg heavy ship. I had no time to build in XL motor with correct transmission.
Electronic behind was made by one of my LUG members and it can operate independenty of any computers. 'Controler' is loaded with program from PC and thats it. Controler can control up to 18 chanels driving them with power up to 12V and 1A par chanel. It can scan for button action or not. Each chanel can be programmed what to do when activated and for dioaramas like this is very convinient. One push of a button of vistor starts procedure like run motor for 17s with (LEGO) speed 5, wait 5s, run motor in reverse for 13s speed 7. Controler can send out even soft start commands for motors, soft stop and break! Additinaly, it can transmit PF command over IR to control remote models like sail ship on train tracks. Additinaly, it can transmit nonLego RC signals and guy build RC receivers that can drive PF motors. At LUG events we allways have problems caused by too few IR chanels and models do unwanted actions caused by other transmitters on the same chanel. Not the end. He put LiPO batteries in small LEGO battery boxes with inbuild charger control, protection circuit...
No need for NXT brick, simply programmed, send program to controler via WIFI and enyoj in functionality.
Yes, it is not solution for LEGO purists but for LUG events it is great and TLG jut not provide any solution even near.