We had this dilemma: The house has two bedrooms and neither one has doors. Because of the layout of the house, there really wasn't any room for doors (without taking up valuable wall space of course). I got to thinking one day, what about using a curtain for a door? You could go any number of ways, light and gauzy, or heavy and dark. We opted for white to look most like what a white original door might have looked like and sort of blend in, and we chose the heavier weight so that it gave the most privacy and would keep heat in the room in Winter and cool in the Summer.
First we found these great rods that fit nicely. They are heavy duty and extra strong to hold the weight of a heavier curtain.
They are called the In Tension Rod. A bit more expensive than a regular spring tension rod of course, but they are VERY strong and can be screwed in if needed for added support.
Next, we chose these great curtains from Bed Bath and Beyond. They are a textured, lined, heavy weight curtain and had the pre-cut holes at the top with metal grommets. They make it much easier to slide onto the rod.
Here is the doorway to the guest room. It's right off the kitchen, so we figured if we had guests that spent the night, it would be nice to have a "door" for them so we bought the same curtain and rod for that doorway.
And here it is closed. Some privacy and it blends in almost as much as a white door would have. It almost just disappears into the wall. They way they slide on the rod makes them fold up like an accordion so they just slide right out of the way when not in use. It's a great quick and easy solution.