I have one week
1. Organize a book drive. If you collect the books, Reader To Reader will make sure they are sent to a needy library or school somewhere in the United States. Did you know that 60% of underprivileged children don't own a single book? Reader To Reader serves the nation’s poorest communities, including inner-city schools, Native American reservations, and poor rural towns.
2. Organize a fundraiser for Homes For Our Troops. This is a rapidly growing non-profit that builds special homes for disabled veterans so that they can have maximum freedom of movement and live more independently. I think a week is a good chunk of time to organize some kind of fundraiser and you'll find suggestions on how to do it here.
3. Here's another book idea. It will be ongoing, so I put it in this category. What you are going to do is set up a book exchange in your work place, apartment building, dorm etc. What you need is a shelf or place to hold books. You also need a sign and a jar or box for money. Find some books that you are ready to pass on. Put them on the shelf under the sign which will say "Book Exchange. Take one and donate one. OR, donate some money." It could be 25 cents for a paperback and 50 cents for a hardcover, or whatever is appropriate for your area. Add to your sign noting that all money collected will be donated to ___. Because it is books, I'm partial to a literacy organization. Or you could pick an organization listed on this site! This is another win, win kind of deal and people will love you for taking the initiative.