Fm radio

Need to check out GNU Radio

GNU Radio is a free & open-source software development toolkit that provides signal processing blocks to implement software radios. It can be used with readily-available low-cost external RF hardware to create software-defined radios, or without hardware in a simulation-like environment. It is widely used in hobbyist, academic and commercial environments to support both wireless communications research and real-world radio systems.

GNU Radio is licensed under the GNU General Public License (GPL) version 3. All of the code is copyright of the Free Software Foundation.

and also the Radio Receiver which gives you FM radio on your chromebook

Radio Receiver is a Chrome application that uses an USB digital TV receiver to capture radio signals, does FM demodulation in the browser, and plays them through your computer's speakers or headphones. This is called SDR (Software-Defined Radio), because all the radio signal processing is done by software running in the computer.

Radio Receiver is 100% written in JavaScript, but is nevertheless fast enough that it can run on a 2012 Samsung ChromeBook laptop at full quality.

Gnu's Not Unix, because Unix is proprietary software while Gnu is software that respects your freedom.

General Public License = A sane copyright license