If you ask for ketchup (and you must ask for it ... it's not offered or brought to the table when the meal is served, nor is it available on the table), you will get it -- lots and lots of bottles of it. When the next table asks, you get the privilege of taking the bottles to them. It's hilarious when someone asks who doesn't know how the request is handled.
The big (!) soda glass (or water) is another WCC "joke." If you "pester" your server for a LARGE drink or refills of water, you might end up with the super-duper sized glass.
The antics depend a lot on your server ... some are wild and crazy while others are a bit more laid back. Be warned... some antics might get you put in "jail" at your table (they bring out some framed bars and you have to spend your meal (eating, too) "behind bars!"
Other antics (none of these are guaranteed to produce any results and be warned your mileage may vary depending on your server):
-- Ask where your server's six-shooter (not "GUN") is
-- Ask for directions to the restrooms
-- Ask for directions to Universal Studios
-- Wear a hat or T-shirt from Universal Studios (other Orlando attractions may work, just not as good as Universal)
-- Ask where you can buy gum at WDW