To truly come out of nowhere and, like a Disney fairytale, dominate those around you like they are unworthy to be in your presence. It is different than being "Tebowed," which implies being beaten by someone with inferior skill and talent, but who was once capable of excellence at a less-than-elite level.
Linsanity, simply put, is an awe-inspiring display of talent by one who was unrecognized of possessing such talent by the "experts" in that particular field.
Max K: Did you know that Manny Pacquiao was once a sea urchin in the streets of the Philippines, unknown to the world, before becoming an 8-time world champion in boxing?
Floyd M: Really, that is pure Linsanity!