gotta wonder what they are going to come up with next !!
YouTube - Unbelievable beer machine.flv (http://www.youtube.com/watch?v=qKQuxEiK3FI)

The perfect fill every time! Note that they don't show anyone drinking afterwards: dribble glass?

after looking at a few more vids , it looks like there is a 'plug' of some kind on the bottom of the cup .

i want one or four

Overthinking IMO. The technology already existed. Many fast food places have the soda machines that will dispense the right amount of soda to fill a cup, whether it's small, medium or large just by pressing a button. Wouldn't need the special cups either.
Posted from my iPhone/Mobile device

I have seen these in person.

The cup has a one way valve and the machine is set to a predetermined amount say 16oz.

It has a few advantages;

No over pouring by staff

When the keg "kicks" it doesn't spray all over the place because the gas doesn't have enough pressure to go up.

It's fast and foul proof

I've seen them used a beer
shows or conventions.

In the time it takes one beer to be poured from a traditional tap at least 4 are done by that machine.

The cups and machine are big dollars. But the big companies had a hand in developing the technology.
Posted from my iPhone/Mobile device

i love this comment

"I can make a few dozen educated guesses at how that machine works. I can apply logic, rationality, basic engineering concepts and yet I keep reaching the same conclusion. It's magic."

That is slick! i wonder how much each cup costs?