"Not a Father's Day" is the seventh episode in the fourth season of the television series How I Met Your Mother and 71st overall.
He is so happy he dances down the street to Marshall's office where he announces he is going to create a holiday for childless men like him called "Not a Father's Day".
Robin says that although Ted does not have children, he often lectures the rest of the group and tells bad jokes like a father would.
Ted replies that Robin is afraid of babies, not wanting to hold them and letting them sniff her like a dog.
She quickly causes trouble, pulling out Marshall's files, throwing up in his trash bin, dancing around and stripping in the background of his presentation.
Ted and Robin go to the bar and encounter Barney's Not a Father’s Day group, proudly celebrating the fact they are childless.
As the episode ends, Barney is seen at the karaoke bar, tearfully singing "Cat's in the Cradle" while holding the sock.