The noise you make when you refuse to listen to somebody and drown out their words with your own noise. Usually accompanied by sticking your fingers in your ears or shaking your head.

A stupid person; it refers to the lack of surface area on an individual's brain. The general thought is that the more surface area (wrinkles, creases, etc.) a brain has, the smarter the person is. Conversely, a person with a smooth brain (no wrinkles) has less surface area and would therefore be stupid.

It's what you say when you've been in your house all weekend studying/working/doingyourstupidf*ckinghomework and on the verge of going literally insane and since you are going so delirious you say random stuff, like lalalala.

ELMO'S WORLD
poeple usually say this at random times when bored out of their minds