If you have a stack of free time and not sure how to use it, here are some projects that might interest you:

Create an Unattended Windows Setup CD/DVD
Creating an unattended XP Setup disc makes installing XP quick and easy. You can create an 'answer file' that will tell setup what regional and network settings you want to use, you can add your own extra drivers so that you don't need to install them later, you can also get Windows to automatically install common software (such as MS Office, Nero, Adobe, etc) and other updates in the order you specify when Windows boots up for the first time.

Estimated time to complete - 1-2 days (if you get it right on your first attempt).

Create a Multiboot DVD
Undertake this project to create a bootable DVD that contains a menu that allows you to choose to boot into different versions of Windows setup (98 - Vista), as well as other tools such as the Ultimate Boot CD for Windows, Bart PE, Acronis and Norton Ghost (if you have these setup discs). You can also add your Unattended XP disc to it.

Estimated time to complete - 1-5 days (depending on how many items you add to the DVD and on your success).

Related Links:
Multiboot Forums
Offline Multiboot PDF Guide

Setup IE7 to Search for MP3's
Using a "Google Hack" to search for MP3's can require a little skill, but doing it right produces more benefits to using P2P programs - faster download speeds, less rubbish in the results, and links to tons of other artists that you didn't think to search for.

Estimated time to complete - 2-10 minutes.

Learn the Basics of Programming
If you've ever searched for a simple free program on Google that would make your life just that little bit easier, it might be worth your while learning how to make your own ones. Using software such as Microsoft Visual Basic .NET 2008 Express (which is a free 62mb download), you can create very simple applications or very complex ones - the choice is yours.

Coding might sound hard - but most basic applications involve you changing the Properties and using maths. All the tutorials are on the Microsoft website, as well as countless other sites that you can find by using Google.