Coollaboratory liquid metal Thermal Interface Compound
 

To be frank, I'm not entirely certain that "Coollaboratory Flüssigmetall" is legitimate, actually has a thermal conductivity of 82 W/mK, is safe to use, or even non-toxic. The manufacturer does not disclose the materials... and the resemblance to mercury is hard to get past.



http://frostytech.com/permalink.cfm?NewsID=44900