Paradox

Noun - 1. A seemingly absurd or self-contradictory statement or proposition that may in fact be true. 2. A person or thing that combines contradictory features or qualities.
Origin: Originally in the sense 'statement contrary to accepted opinion'. From the Greek 'paradoxon' - 'contrary opinion'.

A living paradox: according to the laws of physics, bumble bees shouldn't be able to fly.

This is a great word to describe a concept which is (paradoxically) quite simple but surprisingly difficult to comprehend. Having had a look at the Wikipedia page about paradoxes, picked myself up off the floor after the resultant brain twisting and meltdown (much like what happens to the Internet if you type 'Google' into Google) I figured that the best way to describe a paradox is with an example. The simplest of these is: 'This statement is false' which is true or false or neither or one but not the other or either.... [author picks himself up off the floor again]
Well, you can see what I mean: a simple word which is fun to say and has an 'x' at the end (always a bonus, in my book) for a fiendishly simple concept. Hooray for paradoxes, the evil gits.