Well, you've been here a couple weeks now, so you've had time to settle in to that dull, boring, and probably slightly cramped room of yours. Now would be a good time to brighten up the room a bit, and make it the envy of all your neighbors, or at least the envy of that weird kid down the hall. Believe it or not, there's actually quite a bit you can do to fix up your room, without forfeiting your entire security deposit in the process.
The Floor
This is where all your stuff will end up sooner or later, so you may want to take a picture of the floor while it's still visible (if it's not already too late). Try to keep piles of stuff to less than a foot high, otherwise you may end up losing a roommate, friend, or one of those guys who go around advertising rush events down there. Also, keep track of all the food items in your room, unless you enjoy playing "What's that smell?" Using a vacuum every once in a while helps too, but it isn't necessary.
The Ceiling
The most common thing to put on the ceiling is a set of those glow-in-the-dark stars. Many rooms come with them already installed, so check before you buy them. Sometimes they get painted over, but those stars will glow through a thin coat of white paint rather easily. Also, ever since plastic wrap has been available in more colors than clear, wrapping colored plastic wrap around a light has been a common practice. However, do NOT attempt this on anything other than a fluorescent light; incandescent and halogen bulbs tend to try to melt and burn stuff if given the chance. Nobody but yourself is responsible if you end up burning a building down because you put pink plastic wrap on a halogen lamp so you would have a hot pink room. If you don't know what kind of bulb is in your light, then leave it on for a few hours or days or so, and then hold the bulb firmly with your bare hands. If you smell seared flesh after a few minutes, then you should probably not put any plastic wrap on that light. You should however call the EMS, but once again, nobody but yourself is responsible for any injuries sustained during this procedure.
The Door
This is usually where people put some kind of dry erase board. This way you can be sure that nobody came to see you while you were gone. Be sure to use a different color marker every once in a while, people usually get tired of sniffing the black ones after a while (and don't try to sue anyone if you somehow hurt yourself while trying to sniff a dry erase marker, in case you haven't noticed, anything you do as a result of reading this article you do at your own risk, although gifts, especially monetary ones, are greatly appreciated). In addition to a message board of some kind, decorations matching your personality will help to show people that you have way too much free time on your hands. For an example of the "tape everything to the door" approach, take a look at http://mml2.res.wpi.net/rh321.html, and for an example of a more simple approach, go to http://mml2.res.wpi.net/rh220.html. If you somehow hurt yourself doing that, then you have some pretty bad problems, but nobody involved with this article in any way will take any responsibility for your actions, no matter how bizarre.
The Walls
This is where you will have the most space to work with. If you have cement walls, then you will probably be limited to using tape to attach things to the wall. If you don't have cement walls, then you will probably be able to use drills and staple guns as well. However, if you put holes in the wall, then you should have some way to fill the holes back in. I won't cover that, since filling in holes isn't really decorating. A staple gun is a very useful tool, especially when you want to put something up quickly. It is also rather useful on annoying people who won't leave your room, but you shouldn't do that, and you're on your own if you do. Papers, posters, bubble wrap, clothing, and some foods are examples of things that can be stapled to a wall, the key is to be creative. A drill is handy for those larger items that can't be stapled. Simply drilling a hole for a screw, a set of screws, or a hook, is all that is needed to attach items like clocks, thermometers, outlet strips, phones, small speakers, small appliances, and many other things to your wall. For larger items, you can attach brackets of some sort to the wall, or you can drill larger holes and insert screw mounts into the wall. Items will be more secure this way, but excessive force could cause a rather large chunk of the wall to be removed. You are responsible for any damage you cause, but be sure to take pictures, because gaping holes in the wall are always good for conversation. Finally, a combination of both the staple gun and drill can be used to attach various other items to the wall, making almost anything a potential wall decoration. Creativity is needed here, but this is the perfect way to express your individuality, and also scare your roommate(s) at the same time. I would recommend free stuff for this (you know, that stuff you turned down because you didn't have a use for it, well now you do), especially CD's and those AOL disks (or at least the ones you aren't already using for coasters, bookmarks, deadly weapons, etc.).
The Window
There isn't much you can do here, other than stick stuff to the glass. I guess it depends on the window though, so you're on your own. Just don't jump out of the window, I don't think Plant Services would appreciate the mess. They do a lot for us, so try to keep all the blood and body parts inside.
Despite all of this, the one thing that can brighten up any room the most is still usually a member of the opposite sex (or same sex if that's what you prefer). So, if you're a female and you'd like to brighten up my room, just get in touch with me, a resume and a list of references are optional. And finally, the author of this article, Newspeak, WPI, and everyone else in the universe will in no way be responsible for anything that happens as a result of this article, unless it's something good.