Not that I have an empty closet, but i do like this."Closet Office" - Turn your un-used closet/reading nook into an office space. Maximize the little space with lots of shelving and storage *LIKE CORNER DESK/nook & shelving for office corner
Try a Stylish Skylight - Comfortable Guest Baths - Southernliving. An attic is often a great found space for an addition. Adding a skylight to this space takes advantage of the roof slant to provide ample light and a rustic view.