I saw this from Atmel today on Google+:
Arduino overclocked with liquid nitrogen
http://atmelcorporation.wordpress.com/2013/08/19/arduino-overclocked-with-liquid-nitrogen/
A modder named Michail recently snapped up some liquid nitrogen in Moscow and decided to try his hand at overclocking an Arduino with the LIN. As you can see in the video below, the Arduino’s temperature was brought down to a cool -196°C/-320°F as it hit speeds of 65.3MHz
Video of the chilly Arduino:
Any got the supplies to try this? 
cheers,
drew