Handmade Hero is an ongoing project by Casey Muratori
to create a complete, professional-quality game accompanied by videos that explain every single line of its source code. The series began on November 17th, 2014, and is estimated to run for at least 600 episodes. Programming sessions are limited to one hour per weekday so it remains manageable for people who practice coding along with the series at home.
For more information, see the official website at https://handmadehero.org