Here are some examples of re-purposing I've used with clients recently:
1) Taking a shoe shelf that wasn't being used in the closet and putting it by the front door where shoes were sprawled all over the floor (an example of simply relocating an item to where it's more useful).
2) Using an empty tissue box to corral a drawer full of empty plastic bags to be re-used. This example also saves lots of space. If you re-use plastic bags, containing them is very important and a tissue box works wonders to contain lots of bags in a small space.
3) Using rolling mesh bins being underutilized in a toy room to contain balls and other sporting goods in the garage. The rolling feature made them much more useful in the garage where they can be rolled out on the driveway for easy play. Their larger size also made them more useful for larger items like balls and water toys, rather than small items in a toy room.
Real Simple likes this idea of re-purposing so much that they have a regular feature in the magazine, a web page, and even a new book dedicated to New Uses for Old Things. Check it out for some creative solutions to common household issues. Some of the ideas I find a bit far-fetched, but some of them are absolutely brilliant...in any case, there's no doubt they will get you thinking!
Bottom Line: Next time you're re-organizing a space, think creatively about what you already own. You just might find you have what you needed all along. And don't be afraid to use things unconventionally - if it works for you, that's all that matters! What examples of re-purposing have you used recently?