I need a website development project idea [on hold]

I want to make a website project for Web Development Class and I need an idea.

I know there are many ideas but our instructor wants from us to write a list of problem(s) and then let this website be the solution for these problems.

I am thinking of several ideas but none of them have problems to solve.

I thought of making a how-to website (like ehow.com). But I didn't know how to state the problems in which the site will solve.

Languages we are going to use: HTML / XHTML / CSS / JavaScript / Jquery.

Thanks in advance.