I stepped on my glasses this morning, a lens popped out. A little googling, a little youtubing and the below video showed me how to fix it easily.
It is amazing how I take this for granted. Ten years ago I would drive to a glasses store, and hope they would do it for free. Odds are I would pay $20 and spend an hour doing this. Instead, it took me five minutes. We just assume this level of knowledge is out there for everyone to share in. Amazing.