A different type of "investment." The government is issuing new $100 bills, and collectors are out looking for specific bills. It seems that if a bill has a "fancy" serial number, like 87654321, or 22222222, collectors want them. According to the article, a bill with the serial number 00000001 can be worth up to $15,000 to a collector.
Now, if we only had enough $100 bills to increase the odds of getting one of these "fancy" ones.
For more information, see New $100 Bills Worth up to $15,000