This day lands on June 15 ,and it is a day where you get to chuck your grandma down a flight of stairs to your hearts content.
Person 1: Hey grandma... You know what day it is.
Grandma: No sweetie I don't know what day it is
Person 1: Follow me up these stairs, and stand at the top with me and don't move
Grandma: Okay
Person 1: <Chucks grandma>
that's national chuck your grandma down the stairs day
A term made up by the 'Diary of a Wimpy Kid' used asa 'Your Mom' joke.
Substitute teacher: Greg, can you answer this problem?
Greg: Your Mama!
Subsitute tecaher: Excuse Me?
Greg: Your Big Fanny Granny!
Subsititute Teacher: Well I hardly think that's -
Greg: Your Slaphappy Grandpappy!
a sentence no one has ever uttered except me. why i have ever thought of this is beyond me. help me. help us. you are the only other person to ever see this. except for the poor soul who reviews this.