Amateur radio, also known as ham radio, is a hobby that involves experimenting with radios, antennas, and other equipment to communicate around the world. To participate, one must obtain an amateur radio license, similar to a driver's license. Hams can set up radio transmitters to talk to people worldwide, build their own antennas and equipment, play games locating hidden transmitters, provide emergency communications when other systems fail, contact the International Space Station, and more. The document introduces various activities and uses of amateur radio.