We've probably done these, but:
The character that develops a pronounced tic every time someone like Frank Spencer/Maxwell Smart/Marmalade Atkins enters the room. Bonus points if it's an ulcer and they have to drink milk for it.
The bloke who accidentally arranges two dates on the same night and decides to go through with it, eating two meals, paying for (- gulp - ) four meals, excusing himself to run back and forth between tables, possibly even changing coats etc until he gets in a terrible mix-up ("Weren't you wearing a green jacket a minute ago? And why is there a kipper sticking out of the pocket?") and, ultimately, caught out.
Oh, and the fellow wearing the totally obvious and unsuitable "undetectable" toupee.