National "That's What She Said" Day
An unofficial holiday created by Facebook users. It is said to occur on October 13th of each year. On this day, one is supposed to be especially vigilant of sexual innuendo and double entendre in their conversations with others. When a statement is made that fits the latter characteristics one is to reply with "that's what she said".
Jessica: "I thought it would be longer."
Rob: "That's what she said!"
Jessica: "Ew, pervert!"
Rob: "No, No - it's okay. It's National "That's What She Said" Day."
Jessica: "Oh, that makes sense."