Beer koozies (aka coasties, coldy-holdys, stubby holders and a multitude of other names) are a summer staple for keeping cans of drink colder, longer. Not satisfied with the cooling capabilities of these foam cylinders, Curt Peters created the Chill Puck, a small hockey puck-shaped disc that fits on the underside of a can.
According to Peters, the Chill Puck uses "NASA-designed equipment" originally used for chilling nuclear reactors in cold war-era satellites. The design team also tweaked the ice pack gel to allow it to reach lower temperatures than standard ice, which is why it is able to keep a drink colder, longer.
As an added bonus, the feet on the bottom of the Chill Puck keep condensation from dripping all the way down, so it also functions as a coaster, while a "Chill Band" keeps the Puck strapped firmly in place.
The device is shaped like the bottom of a can so as to maintain the most possible surface area contact with the underside of the can. It is this connection Peters says sucks the heat out of the can and into the ice pack, keeping drinks roughly 10° F (5° C) cooler than a Puck-less can over a 20 minute period.
Peters is seeking funding for his Chill Puck on Kickstarter with a modest goal of US$7,500 – as of this writing, it's sitting at a little over $1,500. The minimum pledge to secure a Chill Puck is $5 while the early bird special lasts, after that, a pledge of $8 is required.
The Kickstarter pitch (which is one of the funnier ones I've seen) below provides more information about the Chill Puck.