I've kept some before. I've had two males, two females. It's important they are kept in groups, and have a very large cage. They love to burrow, so provide lots of woodchips (not pine or cedar). They love to chew on wood, so give them non toxic wood..wood houses, wood anything. Provide a metal wheel for them as well, they love it. For food, they love hay. Mine always loved fruits and veggies, and peanuts as well. If you can look into making your own degu food, it's a lot better for them over petstore foods. You could look into homemade diets on here:
http://deguworld.proboards.com/thread/15670/homemade-mixes
They are really awesome pets
A lot of people take care of them as they are hamsters, rats, mice, etc. But they are certainly something else. They could run around the house, and could respond to their names as ferrets would.
Also as Jenne said, dustbaths are a must. But I contradict males spraying urine, mine have never done that.