The Smart Coaster is an intelligent coaster for your beverages. It recognizes the different types of beverages placed on top of it, with a cocktail the Smart Coaster glows in some atmospheric and slowly changing colors. If you place a cup of hot tea on it, it automatically starts a special tea timer program which shows you, when the tea is ready to drink. If the glass is empty or filled with a cold drink the Smart Coaster glows blue, if the drink within the glass is hot, it glows red.

More information: 

http://www.instructables.com/id/Arduino-controlled-smart-coaster/

http://www.mariolukas.de/2013/10/arduino-gesteuerter-getraenkeuntersetzer/