Season 7, Episode 2 of Friends is called The One with Rachel's Book. Joey tries to take a nap and stumbles into Rachel's bedroom, finding her special book. He reads it and realizes that it is a dirty book. He pokes fun at her and shares that secret with all of her friends, making rude jokes about it. However the audience never finds out the name of the book. Only bits of the plot is revealed.
Season 9, Episode 19, The One With Rachel's Dream
Season 5, Episode 3: "The One Hundredth (The One with the Triplets)"
His name was Mr. Heckles, but he died in Episode 3, Season 2.
Season four: Friends & Lovers
Season 4, Episode 4, The One with the Ballroom Dancing
Season 4 episode 12The One With The Embryos
Season 9|Episode 10 Friends of Peter G
Friends or Foes?
Season 9, Episode 19, The One With Rachel's Dream
Season 5, Episode 3: "The One Hundredth (The One with the Triplets)"
His name was Mr. Heckles, but he died in Episode 3, Season 2.
Season four: Friends & Lovers
Season 4, Episode 4, The One with the Ballroom Dancing
Austin ans Ally's season 1 has only 19 episodes and the name of the last episode in season 1 is Albums and Auditions.The name of the 1st episode in season 2 is Costumes and Courage.
His name was Abraxus, he was the demon who stole the book of shadows in the Season 2 episode "Witch Trial".
"A Lost Claus (Christmas special)" , episode 36 in the 3rd season .
The name of the episode is Cyclone and it is in the 4th season.