Okay. It's Have Fun With Your Slightly Fucked Roomie Day.
Here is how you do it.
Day 1: Start by listening to lots and lots of mp3s. If you have a different schedule than your roommate then call in sick, skip your classes, stay up late.. whatever it takes. Listen to your mp3s loudly enough so that your roommate can hear them, but not so loudly that they complain.
Day 2: Download
Sonique and use it to set the pitch (speed) of your mp3s to 102.5% of their normal speed. Do this when your roommate isn't around so (s)he doesn't hear you initially listening to all your billy ocean records at 150% and masterbating like a crazyman. The idea is surprise.
Day 3: Crank her up to 105%. If your roomie is a particularly clueless music listener, you might want to make each daily increment slightly higher. Likewise, if you're flatmate is a keen listener, crank it down a notch.
Day 4: That's right, 107.5%. As an added bonus, you could spike all their food and drink with powdered caffeine. They'll hardly notice and gee, it'll be a load of fun.
Day 5: 110%. And you thought this was going to be hard.
Day 6: 112.5% Might be pushing it a bit too far. At this point you need to decide if you want to drive them nuts for good or just have a quick laugh at their expense.
Day 7: If your roommate still has not noticed that time is flying by faster than a blonde girl on prom night you might want to announce to him/her how completely ignorant they are. Alternatively, try getting them to drop some acid, crank the pitch while they're tripping, and keep it up after they come down. Talk faster, and move a little quicker. If you could get the 'ol Tivo to play stuff a bit faster on the telly, that's cool too.
If all of that sounds like too much patience and/or work for you, just try shitting under their bed for a few days.