Ok, so I was at a bar last night and in the surface of the bar, there was a cold circular disk meant to keep drinks cold. What are they called? And how long have they been around?

It's a coaster.....

Do you mean just a coaster, or an actual beverage chiller that's colder than room temperature? A chiller isn't anything super special, I have a USB one. A coaster is even less special, of course.

LOL!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

sounds like a gimmick to the bar, probably bought em from some traveling salesman. if you need a coaster to keep your drink cold at a bar. you have a problem.

I figured out what it was. Its called chilldisc

http://chillwell.com/commercial/bars.asp

Pure science fiction