Bookshelves
The shape of the space under the stairs also lends itself to built-in bookshelves. You can choose a cubby style, as shown in the picture below, or opt for shelves that are different in height and width to accommodate your books and also some decorative elements.
Shoe Storage
Hidden Closet
Powder Room
With a little plumbing and electric work and some beautifully bold wallpaper, you can have a fabulous guest bathroom and also raise the value of your home.