Frank Cascarano of Foothills College showed and told us about Coffee Joulies at the NCNAAPT Fall Conference at UCB.
Nutshell: Stainless steel capsules contain a substance whose melting point is 140°F. Pour some 200°F+ coffee onto some Joulies, and the capsules absorb energy so as to melt the substance. This cools the coffee and liquifies the substance in the Joulies.
Once the coffee cools below 140°F, the substance in the Joulies "freezes," giving heat back to the surrounding coffee.
The point is bend the temperature vs. time graph of the cooling coffee to maximize the time during which the coffee is at optimal drinking.
Joulies are officially groovy!
Coffee Joulies from Coffee Joulies on Vimeo.
UPDATE: Marco Arment, creator of Instapaper, was underwhelmed with the real-world performance of Joulies.