When someone asks you a simple question and for no reason at all you have to replay the question in your head, think about it for a second and then come up with the answer.
This can occur when you are either immersed in something else, or just so bored that your brain has decided to take a nap.
Often affects people on medication, alcohol or illegal drugs, but can happen to anyone.
"Dude, was it you that left the gerbil in the fridge?"
"Wha' . . . Ger'um'ah, yeah."
"What the hell have you been smoking? He's shaking like a head-knocker."
"Um . . . your stash. Sorry man got a little Brain Clog today."
When you learn so much in school that anything remotely educational that you read or hear for the rest of the day you are unable to remember.
I'm going to need to borrow your history notes tomorrow. I have a brain clog.