Learn how to use an inexpensive USB software defined radio (SDR) to eavesdrop on pager messages in your area. You would be surprised how many people still rely on this older technology, and you might be even more surprised to see how much sensitive information is transmitted over this insecure method.
I used a radio that uses the RTL2832U chip. There are many of these out there. Most should be under $30 and most should work. These radios are designed to pick up European TV frequencies. That function will not work in the United States, but you can do lots of other fun things with it!