I love the idea of getting more out of the spaces in your home that are generally overlooked. If you have a fairly wide hallway, you could use that space to do double-duty as a small office.
Just find a narrow table and a small chair that tucks COMPLETELY under the table when not in use. Go minimalist with your office supplies. And, if your hallways are dark, use bright colors to decorate and bring in some good lighting.
That said, I have to wonder if sitting in a hallway would feel odd, with roommates or partners walking past you all the time. Anyone tried this? How'd it work out for you?