[tuq]

While nothing annoys me quite like people waking me up by being unnecessarily loud, it is also the responsibility of the sleeper to take steps to avoid being awaken. Earplugs is a good one. Personally, I use a fan. I actually find a complete lack of noise to be loud in itself - "the silence is deafening", as the saying goes. And of course any noise that breaks this silence is that much louder. With a fan set to medium speed most sound is drowned out and I am almost never awaken (well, it doesn't hurt that I live alone, the walls are thick, and the old broad who lives above me lives in a bedroom that isn't directly above so I don't hear walking around).

In short, tell the roommate to take steps to avoid you waking him up. The burden shouldn't fall entirely on you.