Hi JimmyJames,
The fifth state of matter you refer to is called the Bose-Einstein condensate (the four other states are solid, liquid, gas and plasma). You probably heard it in the news somewhere because the Nobel prize in Physics was awarded to research on the BE-condensate

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The BE condensate is a special state of a type of particles we call "bosons" (in technical, quantummechanical words: these are particles that have an integer spin value). Some examples of bosons we know are photons (the light-"particles") or the 2He-nucleus (a Helium atom with all the electrons left out). There's also a second kind of particles called "fermions" (which have a half-integer spin value), with the typical example being the electron.
The main difference between bosons and fermions is that fermions obey the Pauli exclusion principle. This principle states that in a closed system (for example, the electrons bound to a nucleus), no two electrons can have the same configuration. If you have one electron that has a certain energy, angular momentum and spin, then no other electron in that system can have the same energy, same angular momentum and same spin. This is way electrons in atoms all have different "orbits".
Bosons however, do not obey the Paul exclusion principle. If you would consider a system of bosons, then they can all have the same energy, angular momentum and spin. In particular, all boson particles can have the lowest possible energy in the system (we say that the bosons are in the groundstate of the systems). When almost all bosons in this system are in the groundstate, you have a Bose-Einstein condensate (condensate refers to the fact that they all have the lowest possible energy).
The Bose-Einstein condensate has been predicited in theory for quite some time already. Most of its properties have been known for over 50 years.
That's about everything I can tell about what the BE-condensate is. The Nobel prize was awarded this year to an experimental investigation of the properties and characteristics of the condensate. (I'm not quite up to date on the exact characteristics that were studied, but I am sure you can find that on the web somewhere).
Bye!
Crisp