Yesterday we got this advertisement from the Good Samaritan Hospital in San Jose, CA in our mail. It is a 11x6-inch acetate mailer. Hubby showed it to me before tossing and I immediately grabbed it to use for my Mad Lab. As you can tell from the photo it will look like a nice brain scan when lit from behind on a light board. Thought I'd slap a post it note over the bubble and say something like "Remove Brain".
If you live in the San Jose area, you might want to check your junk mail for this advertising piece and use it for something similar. The brain scan occupies about 7 inches of the length of the mailer.