So, I came up with my own easy (fast and cheap!) way to make them. You may even have everything laying around the house already.
One (1) FLAT twin sized bed sheet
Five (5) standard pillows
A measuring stick/tape
Tailors chalk (or your kids colored pencil, ahem)
Lay your sheet out flat and carefully fold in half lengthwise. You'll be sewing across this width to create 5 pockets
Starting at the hem stitching line at the top of your sheet, with your chalk, mark every 18 inches and pin across the line so nothing moves when you pick it up. Your last seam will be at the bottom hem.
Sewing from the folded edge to the opening, be sure to do solid backtacs at the start and finish of each line of sewing.
Repeat with all the lines. As you move across, roll your sheet, so that it fits under the arm of your machine. On your very first and last seams, just sew right along the existing hemline stitching.
You'll have a top flap that is perfect for the kids to grab to move it around, or perhaps attach something to help roll it up for storage
Stuff each pocket with your pillow. These are the pillows I picked up at WalMart. The everyday price is $2.50. If you've got extras around the house, use them! The beauty part of this mat is that the cover can be removed easily to wash it.
We plan to use our mats for movie nights, even tossing them in the back of cars for road trips, drive in movie nights and fort building.
If you make one please send me a picture. We'd love to see it!
(If you have an questions, let me know)