What to do with spare bedroom?

Since our kids prefer to share a room we have a spare. It's gone from everything, playroom, guest bedroom, office, entertainment room. Now it's kinda a mixture of all the above, it has a bed & entertainment center w/tv dvd etc & an office desk, computer, file cabinet etc & even my boys have a spot where they keep their electronic devices like psp's & such, and the closet acts as a winter storage, and freight supply warehouse. But I really need to get a grip on this & start to utilize the space more effeciently, I like being comfortable with what i've got, but i'd like to be able to use all the room available to me.