Here's my contribution:
Series: Ghost In The Shell Stand Alone Complex
Character:The Laughing Man
Foam mounting board (preferably with a navy blue background)
Large Image of the Laughing Man Face
A printer, or a printing store nearby.
Access to a lamination machine
Tape (preferably duct)
OPTIONAL: Part of a Bluray DVD cover, blue hoddie/coat with a hood, jeans.
This is a costume you can make in roughly a day or two, is fairly inexpensive and will probably get some good laughs at the con you go to. First, take the image that I've attached and download it.
Now, you have one of two options: 1) Print it out yourself (make sure you know how big you want it, I made my second version 16 1/4" tall x 18 1/4" wide, the first was a bit smaller), you'll probably be looking at 4 pages for the printout. 2) Bring it to Staples or the like and you can get it on one big piece of paper and laminate when you're there.
NOTE: It is fairly important to figure out where you want your eyes to be early on, so you might want to figure that out first.
After you have it laminated, take the foam mounting board and cut it in the shape of your face. Once that's done, use the glue to mount it on. I used instant crazy glue.
After the face is mounted, cut out a hole for your eyes. My original version had two eye holes, but I found that hampered my vision more than helping it so the second version had one big eye slot cut into the top of the mouth.
Now, here's the optional part. If you have a BluRay cover (or any blue plastic you can see through), you can cut it up and use it in the eye slot to make it look like there's no holes there. I just made 3 slits one the right, left and top sides of the eye slot and cut out part of the bottom to slide it up and secure it in place.
Now, you should have extra foam board. Cut that into a rectangle roughly the size of your forehead and attach it right above the eye slot. This, with the bandanna will act as a buffer to keep the mask from smashing your face in. Roll up the bandanna and attach it to the block. Use tape to secure it and you're done!
I personally bought a blue hoodie to go with the mask since the Laughing Man wears a blue jacket in the series and the hood covers up the back of your head.
Also, here some images of the mask. The first version after it was done and the second version as I did it.