Ask your server for a LARGE drink (anything will do). Make sure he emphasizes the word "large" -- tell him the server may not have heard him, so he'll repeat it. (The server will get the idea!)
I've seen some incredible containers used to bring a "large" drink to the table, along with a nearly 2-foot long straw! One glass looked to be nearly a 1/2 gallon! It is hilarious. Even funnier ... my DW asked for a large water. Our server brought her a glass barely the size of a shot glass along with this 2-foot bright RED straw sticking out of it. I nearly fell off my chair laughing!
Other things that might get your server going:
Ask where you can buy gum at WDW
Ask for directions to the restrooms
Ask for directions to Universal Studios
Ask where your server's six-shooter (not G-U-N) is
These are not guaranteed to work everytime -- but if you get the right server, it can be very funny.