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I'm doing a class at the local community college that requires me to write a web application (using PHP and MYSQL). Any ideas?

The primary criteria is that it needs to be business related, somewhat original (As in, no phonebooks, etc... things that are commonplace), and needs to implement PHP and MySQL. Needs to be fully functional website. Cannot be a game or anything illegal (obviously).

The requirements aren't terribly rigid, since the project is more a class project (the entire class if focused on this project, each person does their own project).

I'd like to do something business or finance related (my primary interest--computers is really only a hobby--primary reason I'm taking the class is to keep my skills up, to expose myself to current web programming technologies, and so I can get a programming certificate, which I actually don't really need for my job, but more or less want for the future just in case).

Any suggestions or ideas? It needs to be something, however, that I can finish in about 5-6 months (At most). Basically, it can't be a project so large that it takes 10+ hours a day to code for 4 months. It needs to be useful, but also small enough to be done within a few months (I know this is a bit vague because some can write a complex program in a few weeks, and it's more about how much time you put into the project that can determine it's "size".)

Write a program for logging articles. In a business, it could be used for financial documents. For a scientist, he could log his journals.

I thought about something like this (in particular, a personal knowledge base, which was suggested to me for another project). I'm thinking that a personal knowledge base (not neccesarily a CMS system, even though it may act very similar) would be beneficial as people start to store more and more info on the Web.

For the project itself, it would probably be very slimmed down, since I only have one year to write it (and that will be one year in the evenings most of the time), but I may develop it more even after the project is "done and graded."