You also have to 'help' make the fun. Folks can't just sit back and expect the servers to do all the work in making it a good experience.
When we went in August with a group of 15, only my family of 4 knew what this restaurant 'held' in terms of entertainment and fun. All I said to the group was "This place is like no other restaurant you've been to, and you'll learn that a lot of what your mother taught you about eating out isn't adhered to here".
It didn't take long for my group to realize that THEY could have fun with the servers too. One of the assistants started walking past our table, clip-clopping the tray stand and giving my BIL a look everytime he walked past. Well, my BIL found out his name off his tag and said "Next time he walks past, lets SCREAM his name". We did...and the look the server gave us was priceless, and then he smiled broadly. It turned out to be our 'schtick' during the meal, and every time he walked past we shouted his name.
There were lots of other things we did to play along. I will say, there were parties in the restaurant that looked at us like we were crazy...but we were having TONS of fun and just didn't care. We watched other servers get into the antics, but when the group at the table just sits there and smiles a little, laughs a little, the server can't really know whether its appreciated or they're just being polite. Our servers learned right from the start we were willing participants (especially because we really joined in with stuff of our own) and really went with it.
The dinner lasted over two hours, we were having such fun. We agreed that as we were leaving, we'd all march very loudly out through the restaurant and holler "goodbye" to our servers. The manager of the restaurant grinned widely at us as we walked out, as he knew we'd had a terrific experience.