As Alice in Wonderland says "things are becoming curioser and curioser".
First there was a report that the 2D interface between 2 insulators can become metallic. Now a new report in Nature has indicated that such interface can in fact become superconducting, albeit at 200 mK. Fantastic!
This interface is a 2D thin region (~10 nm) and evokes exotic transport mechanism, I would assume. There's still considerable work in coming up the theoretical explanation for this phenomenon. So there's plenty of work left to be done.
 A Ohtomo, H.Y. Hwaing, Nature v.427, p.423 (2004).
 N. Reyren et al., Science v.317, p.1196 (2007).