I finally decided to upgrade from the sheet I had tacked to my wall. I had a small budget, and wanted to be able to take it down when I wasn't using it and this is what I came up with.

Step 1: Materials

I already had some of the materials, so it cost me less than a dollar, but it could be done for around ten bucks.

You need:
-An old sheet.
I'm sure you could find a cheap one at walmart or goodwill or something.
-PVC.
I got twelve feet at home depot for 75 cents, they even cut it for me.
-Eyelets/ eyelet kit
If you don't already have one, they have the kit at home depot for a couple dollars.
-Hooks
The kind with the little screw on one end.

That's about it. I also picked up a pack of velcro straps at walmart for 2 dollars. I needed them anyway for cord management.

Step 2: Construction

1. Decide what size you want. Mine is 5 feet wide by 6 feet tall.
2. Cut and sew the top and sides. Leave a couple inches extra on each side so you can fold it over and sew a seam.
3. Insert eyelets. One on each side of the top.
4. Sew in pvc pipe. This is to make it hang flat and straight, and to make it easy to roll up and store. Just fold the bottom over the pvc, crease the sheet, take out the pipe and sew all the way across. Then slide the pipe in and sew the sides shut.
5. Put the hooks in your ceiling. I put some in my living room, my bedroom, and another bedroom. They're hardly noticeable so I just leave them up there all the time.

Step 3: Enjoy

Hang it up and enjoy. Whenever you're not using it, just start at the bottom and roll it up, then put the velcro straps around it and put it in a closet or something. As always, thanks for reading.

Sidenote:
I thought about cutting the pvc in half and leaving about a two inch gap in the middle so it could be rolled up and folded in half. Whatever works for you.