The micro:bit is a low cost microcontroller board developed by the BBC and a range of partners. You write programs to make things happen with the micro:bit.
You have a choice of languages and can program online at http://www.microbit.org. There are also some offline solutions for Python and C++.
You can also connect a whole host of eletronic components to create all sorts of contraptions or just to learn how to make them work.
Click on the boxes above to scroll the links for a section into view. There are over a hundred pages here, with ideas, examples and challenges to get you started with the micro:bit.