The name of the company Neo worked for in the movie "The Matrix".
The roots of this word are meta-, which according to Webster's means "going beyond or higher, transcending," and -cortex, which is "the outer layer (boundary) of gray matter surrounding the brain." Thus, Metacortex is "transcending the boundaries of the brain," which is precisely what Neo proceeds to do.
Steve (the born again metrotextual) was stabbed in the groin less when he skim read some Margaret Atwood novels and stopped saying, "Hey, I know chicks, I came out of one, didn't I?"
While our lifespan is the number of years we will live, our healthspan is the number of healthy years we will have and our sexspan is is the number of years we will continue to be healthy enough to continue having an active sex life.
A lighthearted reaction upon receiving disappointing news of some sort. Usually something that isn't a particularly a big deal, esp. when it primarily affects someone else - sort of a mild schadenfreude. Sometimes doubled or tripled, and possibly said in a sing-songy voice for added comedic effect to imitate a muted trumpet, which is how the meme originated.