Well, not really. But some German inventors have created a beer mat (coaster) that will sense when your beer is almost empty and notify the bartender. Personally, I prefer the following invention to tell when I need another beer:

Beer Blog
September 29th, 2005 | Beer Tech
Well, not really. But some German inventors have created a beer mat (coaster) that will sense when your beer is almost empty and notify the bartender. Personally, I prefer the following invention to tell when I need another beer:
