For Christmas, received a Baofeng UV5R radio. He didn't have an amateur radio license, so he decided to use it as a police scanner. Since the schematics were available, he cracked it open and hacked it.
This $40 radio communicates on the 136-174 MHz and 400-480 MHz bands. It uses a one-time programmable microcontroller and the RDA1846 transceiver. With the power traces to the MCU cut, was able to send his own signals to the chip over I2C using an Arduino.