One of the reasons that high temperature superconductivity is both so exciting and frustrating is that we do have an excellent theory for superconductivity at low temperatures: the BCS theory (so-named for its three co-inventors, Bardeen, Cooper, and Schrieffer). Unfortunately, although the BCS theory works marvelously at low temperatures, it quickly becomes problematic as you warm up. In fact, before the advent of the cuprate discovery in 1986, most thought that any superconductor even close the boiling point of liquid nitrogen was a theoretical impossibility. Now that the cuprates have shattered that ceiling and the pnictides could soon follow, we are back to square one theoretically and it seems that any transition temperature is an experimental possibility.

And two, though I got the part about high temperature superconductivity being baffling, still I have to ask, do we know enough about superconductivity to rule out the possibility of "room temperature" superconductors, or is that still within the realm of theoretical possibility?