By now you've probably seen Avatar, and are maybe wondering about the odd name for the mineral so coveted by the corporation mining on Pandora. And while it was also used in the The Core, it's not a cheesy term coined by filmmakers, but an actual scientific term.

Unobtainium is the term used by scientists to describe an unknown or impossible to get substance. The name itself is a bit of a joke, but not the first in the scientific or technology lexicons.

In 1947, when one the Mark II computers was not functioning properly, the cause was traced to a moth inside the enormous computer. The act of removing the moth was jokingly referred to as "debugging" and the term stuck for other, non-physical causes of computer malfunctions.

Two years later, the term "Big Bang Theory" was coined by a physicist dismissing the work of a competitor. Fred Hoyle dismissed Georges Lemaître's theory in a 1949 radio interview, as "this big bang idea" and it stuck. It's much more memorable than Lemaître' s hypothesis of the primeval atom cosmological model of the universe, isn't it?

Even more recognizable is "spam," inspired by a 1970s skit by Monty Python, in turn inspired by Hormel's inexpensive potted meat, originally marketed as spiced ham, then as Spam.

But back to Unobtanium. It's also a registered trademark by Oakley for a rubber compound used in their glasses that has increased grip when wet. For a material that's supposed to be unobtainable, there sure is a lot of it out there.