Dont't expect it all the time!
Just a word of caution -
Antics at the Whispering Canyon are NOT guaranteed! Just because others have experienced some antics does not automatically mean you will get some antics! If you go there with high expectations, don't be surprised if you get disappointed.
Now, having said that, you may be witness to some horse races, where the kids ride stick horses through the restaurant. My favorite was the lady who was having a birthday and sent to the lobby to sing Happy Birthday to herself!
When my wife and I were there last November for our Honeymoon, we were seated at a quiet table in the corner. The table next to ours, served by the same waiter, was a large party of 12 with kids who were seated at the same time as us. Our waiter sensed that we wanted a nice, quiet meal, so he would come to our table first in a "normal" manner, then he would go to the large table and pull out all the stops with the antics. We were very grateful for him sparing us the antics and allowing us to dine in peace. And boy was it fun to watch what he put the other table through!
Go and have fun, you'll enjoy it!