Create as many forts out of blankets as you can. Defend them violently.
Give them the 'sex talk' weekly as if you are their concerned parent. Use props and if possible a video/DVD.
Constantly re-arrange the room while they are away. Upon their return, insist you're practicing Feng Shui. If they get upset, start moving things around and checking to see if it makes them feel better. The more upset they get, the larger the objects you start moving around.
Shit in the shower/bathtub and use their towels to wipe it up. Leave the towels folded so they end up not noticing all the shit until too late.
Wait until the TV has gathered some dust and then press your bare ass to it, leaving an ass print. See how long it takes for them to clean it, or notice it.
Put on bad music and 'rock out' by throwing yourself violently around the room.
Blow up their pillow.
Talk to them about their 'future'. If they become hostile, talk nonstop about your 'future'. Make up various careers that you want to have such as Dinosaur Hunter, Astronaut, Salad Fork, Plumber, Captain of the Seas etc.
Spit on the taps all the time and don't wipe them off.
Never empty the garbage, just keep piling more stuff on top or near the full bag.
Try out wrestling moves on them all the time while watching nonstop wrestling shows.
Fill a water bottle with piss. Each day, pour a small amount of piss into their shoes or mattress.
Insist that you only eat catfood. Leave it out in bowls to stink up the room. Actually EAT it, causing yourself to puke it back up.
Develop a nightly routine that involves the following: putting plastic bags on your feet, arranging the content of your drawers by color, name your furniture with "hello my name is' tags, say goodnight to them and try tucking them into bed with your roommate.
Buy their exact wardrobe and wear the same clothes they do every day. Start commenting on how much you have in common, and how you must be twins separated at birth.
Start writing down everything they do that you consider 'wrong' or 'rude' and email them weekly reports.
Put notes on everything explaining what everything is and how to use it. If they are removed, scold your roommate and put them up again, this time in a larger font size. If needed, wallpaper the place with instructions.
Insist on weekly meetings and take notes. Have them sign in on the meetings and vote on stupid topics such as 'the folding of socks for room 391' (substitute your room number unless you'd like to confuse them even more).
When they ask you to do ANYTHING sigh and say 'yes dear'.
Accuse them daily of trying to read your mind.
Leave out brochures and articles for them regarding problems they don't have. They will either think that you have some serious problems and are crying out for help, or that you are hinting that they have the problems.
Ask them daily about their cleaning habits. Always act like it isn't enough. "Oh, so that's all you do to keep your toothbrush safe from droplets of piss?" Bring home disinfectants and clean everything they touch 5 seconds after they've touched it. Behave as though they are crawling with nasty germs and ask "You haven't touched this have you?" before you touch anything.
Instead of tagging things with your name. Label it all with MINE, even their stuff.
Ask them for emergency contact information and their parents numbers in case there 'is a problem'. Also ask about mental illness in their family.
When they eat anything, ask them about it. Come up with as many questions as you can until they tell you to shut up or beat your face in. For example, they're eating a meat sandwich : so that is a dead animal? which one? did you kill it yourself? how do you feel about that? do you think you've absorbed the power of that animal?
Open each chip bag and lick the flavor off all the chips, then put them back in the bag.
Hide one of their shoes every day for about a week. (Or just kick them outside when they're not looking.)
Keep your room real messy for a few weeks. Clean it while your roommate is out. Leave before they come back. Arrive after them and then angrily accuse them of cleaning up your room.
Take all of the hair out of their brush and stick it to the wall with scotch tape.
Insist on cleaning their fingernails for them every night.
Crumple empty chip bags the whole time your roommate is home.
Make a shine dedicated to them.
Whistle one line of a song and repeat it for 3 days, then pick a new line.
Play Scottish music 24 hours a day full blast.
Every night at midnight, stick your head out the window and scream "GO AWAY MONSTERS! GO AWAY!" Do this every night for 6 weeks.
Sniff their underwear while they're still wearing it.
Buy fish and a fish tank. Dye the water with food coloring. Talk to the fish and giggle often while staring at your roommate.
Tie all your socks up in knots. Hang them from the ceiling. Count them every time you walk in the room.
Every time your roommate walks in the room, shake their hand and smile sweetly. If they refuse, wipe the smile off your face, clench your teeth and growl whenever they walk in the room for the next two weeks.
Watch test patterns.
Collect bottles of colored water on the floor. Refuse to discuss them.
Buy lots of slinkys and hang them from your ceiling while humming "It's Slinky, it's Slinky..."
Buy lots of pictures. Hang them up upside down. Stand on your head to look at them.
Tack candy wrappers on your walls.
Buy Barney dolls, tapes and posters. Carry the doll around singing "I love you...You love me..." and paint your face purple.
When your roommate throws something out, grab it from the garbage exclaiming "I can't believe you're throwing this away! I've been wanting one of these for so long!" and toss it in a large card board box. Do this for a month or until the box is full. Then dump it on your roommates bed saying its their garbage anyway.
Talk to "invisible friends" about your roommate. When they look over, look away quickly and smile.
Stare at your roommate dreamily while slightly smiling...all the time.
Refer to them as if they are a crowd of people. Use phrases such as "Could all you guys keep it down?" when your roommate is the only one in the room with you and it is silent.
Demand to be taken to your roommates leader.
Throw eggs at them.
Get a large box of lego bricks, and constantly dig through it looking for a 'certain piece". Swear often and throw the plastic men around. Interrogate the little men and accuse your roommate of conspiring with the enemy.
Throw socks around the room. Name them. Move them around. When asked to clean them up, explain that they are free range socks and need to be allowed to become naturally fluffy and that you're just doing your part for the environment. Then ask what they have done lately.
Get a cell phone. Phone them constantly. When they say hello, stay quiet, then say hello, and then act like they are the one who keeps phoning you all the time.
Act surprised every time they enter and say "oh, I wasn't expecting you until later." When asked to explain, just say "oh nothing. Nevermind." Then pick up the phone, and say "the gig is up". Slam down phone. Pretend nothing happened.
Respond to everything they say with a question.
See how much self groping you can do before they say something.
See how nude you can get before they object.
Start collecting AOL cds as if they were rare items. Create display cases.
Every time you are done in the shower, leave huge hunks of hair floating in the tub or stuck to the wall.
When a new roll of toilet paper is in the bathroom, get a grocery bag and fill it with all but one sheet of the toilet paper. Keep the extra paper in your room, and if you have too much then start stuffing pillows with it. Try selling the paper outside your door and hide it when your roommate comes by. Don't forget to bring toilet paper with you when you go to the bathroom.
Paint the walls with peanut butter as if you were using paint.