6. Get some pets -- preferably two hyperactive cats and a bird.
7. Get a pet rabbit. At a designated time every day, take the rabbit into the bathroom and engage in loud shouting matches. If your roommate inquires, refuse to discuss the situation and say, "It's between me and the bunny."
8. Get a dog or cat. This one only works if your roommate is not fond of four-legged creatures. Make it clear the pet is there to stay and will have the run of the house. People who don't like animals can rarely stand to live in the same house with them. Besides, a cat or a dog will be easier to clean up after than the erstwhile roommate.