Marisa Rules
Use BBQ tongs to retrieve cell phones and other necessary items from the toilet.
Wash your hands before eating, unless you're eating dirt or cafeteria food.
Arrive to class on time. And by on time, I mean within that 30 minute grace period at the beginning of class.
Put things back where you find them, unless you want to mess with your roommate. Her pillow can easily be hidden under the sink, her shoes in her purse, and her chem book behind the mini fridge.
Look both ways, unless you're at the end of a cul-da-sac.
Throw a bi-monthly Christmas party. 
Share everything, except underwear, mouthwash, boyfriends, and your Lost DVD collection (or any other DVDs you might want to watch again.)