– https://habitica.com
– https://www.ted.com/talks/jia_jiang_what_i_learned_from_100_days_of_rejection

– CodinGame: https://www.codingame.com
– CodeCombat: https://codecombat.com/
– Human Resource Machine: http://tomorrowcorporation.com/humanresourcemachine
– Shenzhen I/O: http://www.zachtronics.com/shenzhen-io/
– Screeps: https://screeps.com/
– LightBot: https://lightbot.com/flash.html
– CodeCademy: https://www.codecademy.com/