Go up to the maitre 'd and request a table and while he's checking to see if one availible loudly proclaim "IS THAT A ROACH RUNNING ACROSS THE FLOOR... Ohh MY GOSH IT IS"
Another good one is to bring along a date who's a shrieker. Pinch her on the butt and, right after she hits a high note, point at the floor and yell, "That's the biggest damn rat I've ever seen!"