The Patented Daydream Charm was a magical item created by Fred and George Weasley, and sold at their shop in Diagon Alley, Weasleys' Wizard Wheezes. Virtually undetectable, they produce a very realistic daydream lasting for thirty minutes. Side effects may include drooling and/or dazed expression. They were not sold to customers under the age of sixteen, and like all Weasleys' Wizard Wheezes products, they were strictly banned from Hogwarts School of Witchcraft and Wizardry by Caretaker Argus Filch.
Hermione Granger found the product an extraordinary piece of magic, which was saying something, considering that she once stated the only thing the twins knew was "flashy stuff that's no use to anyone." For the compliment, Fred offered her one for free.
The colourful cover of the box Hermione was looking at showed a "handsome youth" and a "swooning girl" on a pirate ship.