The BBC micro:bit is a small development board, based on the 32 bit ARM Cortex M0 microcontroller. It includes a compass, accelerometer, Blutetooth LE, an LED matrix and i/o connections for integrating sensors, LEDs, buttons etc.
The board was developed by the BBC for children and young adults and was highly influential as it was delivered to over a million children in the UK. It is used for teaching programming and creating with digital tools.
Development tools, inspiration, support and much more is available on the micro:bit website.