you can make fabric from plastic bags!
You will need:
-an iron
-a place to iron (i.e. an ironing board)
-2-4 large pieces of cardstock or posterboard
-a cutting device (i STRONGLY recommend craft knife or rotary cutter, but scissors will suffice)
Step 1: Collect a whole lot of plastic bags. (Grocery bags, dry cleaning bags, etc.)

Step 2: Straighten and smooth each bag.


Step 3: Prepare the bag. Cut off the base and handles.



Step 4: Open the bag up. Cut up the side of the bag with a scissor.

Step 5: Smooth

Now you are ready to actually create the "fabric." The fabric will feel somethign like tyvek, which is traditionally used to wrap houses, but more recently used in jackets (american apparel has one). It is very lightweight and durable.
Step 6: Get out your ironing board (or other ironing surface.) Lay down your cardstock, and then 5-8 plastic bags on top of each other. More bags will make a thicker fabric, but also take longer to iron. I used 6 bags.

Step 7: Turn on your iron. I used the setting for cotton blends. The rayon setting works well too.
Step 8: Line up the pieces and iron them together. Be sure to put a piece of cardstock on top of the stack. If you do not, the plastic will melt directly on your iron and you will RUIN YOUR IRON. Go back and forth, pressing firmly down on the iron.

Do not remove the top piece of cardstock until it has cooled. Not only will you burn yourself, but you will create holes in your fabric. Also, resist the urge to turn the heat on your iron up higher. It will not speed up the process, it will melt the plastic and create holes such as these as well.

Step 9: Take a look at your fabric. Has it all fused together? If so, you are ready to sew with it! If the fabric still has parts that feel like plastic bag (below), continue to iron using the above method until it has fused.

Step 10: Enjoy your fabric!

Try different color combinations. I figured out that it works best if you use all one color, or a color with white. Brown tends to make colors murky, so try to use brown alone, unless you want that murky look intentionally. Clear dry cleaning bags will create a see through fabric.
You can run the finished fabric though your sewing machine. I suggest that you try a sample piece before beginning a project. I didn't need to adjust my tension, you might need to, depending on your machine.

The "fabric" can be attached easily with hot glue. The glue will melt and bond the bags very firmly. Once you have fused the bags into fabric, you can cut it easily with a scissor.
Here is what I did with the fabric:
http://www.craftster.org/forum/index.php?topic=178445.new#newit can also be used as a cheap, environmentally friendly heavyweight interfacing for bags, camera cases, etc.
No, it does not sound like a plastic bag when you wrinkle it up.