By all means, don't stop at paint treatments; get creative with wallpaper remnants, too. This designer went to romp for the adorable lion cut from vintage wallpaper (placed above green chalkboard paint), but you can find great decals from Dezign with a Z or cut your own shapes.
Another project on my mind is swapping out — or at least dressing up — closet doors. We have giant mirrored sliding doors that I would like to replace with contemporary frosted plexiglass versions. Even applying vinyl decals or wall paper to basic white closet doors is enough of a change to spruce up a bedroom.