If your office is as bright as ours (which is pretty damn bright by the way), its great because you'll be able to see tons of things around the office, but it also means that you might have to deal with a lot of reflection and glare on your monitor. While you can buy a monitor hood for cheap, photographer Roger Sacul has a cheaper option, and its a DIY solution.
Sacul goes for the long lasting method using a sheet of cheap plastic. But if you're not keen on that you can use a foamboard which is a quicker and easier method.
Draw a few lines and make the cuts, and assemble it, its pretty easy. The results are as good as money can get you. Hit up the full post over on DIY Photography for the step-by-step guide to making one yourself, including tips on getting the specs on your monitor or laptop.