Ok, so the title of this post is perhaps misleading. Bell Labs didn't invent the music video. :-)
But they did invent or discover an astonishing number of other things: negative feedback amplifiers, the transistor, cosmic background radiation, the laser, the UNIX operating system, the list goes on. Bell Labs amassed 13 Nobel prizes between 1937 and 2000. As I've delved into telephone history for my phone phreaking book I've been amazed at how many technical challenges Bell Labs and the Bell System encountered and overcame.
Historian, legal scholar, and network neutrality guru Tim Wu suggests in The Master Switch that Bell Labs was basically a research and development tax levied on the American people through their telephone bills, thanks to AT&T's status as a government sanctioned monopoly. I wish the taxes we have today could be so effective. Here's a several minute music video tour through their accomplishments:
Be warned, the innovatoins are going to come at you pretty quicky. Score one point for every name or innovation you're familiar with.