For more than 60 years, Germany's Fraunhofer Institute has promoted and undertaken "applied research...of wide benefit to society as a whole," according to its mission statement. That's why it's not at all surprising to hear that they recently came up with the Perfect Coffee Mug, a temperature-regulating drinking receptacle that keeps coffee at the ideal drinking temperature for up to 30 minutes.
The mug uses phase change material (PCM)--that's a substance with a high heat of fusion that can store and release energy (heat) over time. By adjusting the amount of PCM in a given object, you can effectively set the temperature you want to maintain. The Perfect Coffee Mug is set to about 136 degrees Fahrenheit.
Here's how it all goes down: you brew your coffee, optimally at 200 degrees Fahrenheit and pour it into your mug. Maybe you lose a few degrees in the pouring, but you're still probably be looking at around 195 degrees, what we in the science biz call "tongue-scaldingly hot." So your mug absorbs that extra 60 or so degrees and gives it back slowly, as your coffee cools, to maintain its ideal temperature of 136 degrees.
I, personally, can think of nothing that serves society better. When these mugs hit my local Target, you can bet I'll buy a bunch.