If you are not fascinated about superconductivity and think that it is one of the most complex and rich system that we currently know, then you're missing A LOT!
We know about Type I superconductors and Type II superconductors. But a group of researchers have concluded that MgB2 is a Type 1.5 superconductor! It appears that MgB2 can be a Type I and a Type II at the same time! It arises due to the fact that this compound has two different bands that are responsible for superconductivity. The paper argued that a Type I superconductivity resides on one band, and a Type II superconductivity resides in the other.
If this is true, it will be the first time we have observed a material exhibiting this new superconducting state. And added another level of unexpected complexity and richness to the field of study.