If you tour the Federal Reserve branch on Conway Street, you can get a little baggie of shredded currency. Each piece of the former money is like 2 millimeters wide. I took a couple home to my kids and they briefly tried to reassemble the bills. Unsuccessfully.
However, some enterprising Chinese with the help of some Lufthansa flight attendants are alleged to have made some 20 million euros in a similar enterprise. HT Marginal Revolution.
From upgrd.com: