Don't talk to strangers - except at Christmas when I tell you to go talk to that fat guy in a red suit. Wait, don't just talk to him, sit on his lap! And be happy about it.
It's not polite to ask people to give you things - except at Christmas when you can tell a complete stranger to bring you a whole list of stuff, and at Halloween, when you walk around demanding that people give you candy.
Never eat anything you find on the ground - unless it is Easter - then the more you pick up off the ground, the better egg-hunter you are. Eat up!
It's mean to pinch - unless it's St. Patrick's Day. (eurgh - that one causes trouble!)
It's rude to ring the doorbell and run - unless it's Valentine's.
And I'm sure there are more that elude me right now. See what I mean though? Warped!