Look at them often. One day, act surprised and angered, and accuse your roommate of having released one of the gases. Cover your nose and mouth and run out of the room. Wear scary Halloween masks. Look in the mirror and scream hysterically for about five minutes every time you put one on.
Roller skate up and down the hallway.
Stick your head out the window, but forget to open it, so that your head crashes through the glass. Act like you hit your head on something. Dress like a military officer. Insist that your roommate salute you upon sight. Keep a collection of teeth in a jar.