cabinets, stairs with flip up steps and very narrow stairs. Each step goes up one at a time for each foot. It is sort of spaced so you are putting one foot per step with a steeper step. Very space-saving.
Bookshelf stairs -- I like these a lot better than other versions, because there are no books on the stairs themselves, which looks cluttered. I feel like even with my limited carpentry skills, I could build these.