MIT's app only needs a second to teach you a new language
 

You know the seconds and minutes you waste waiting for the elevator to arrive, for a friend to reply to an IM or for a website to load? A team of MIT CSAIL researchers believe you can put them to good use, so they created a series of apps called the...

https://www.engadget.com/2017/04/18/mit-waitsuite-apps/