Leonard: So, how do you two know each other? Missy: He once spent nine months with my legs wrapped around his head. Leonard: Excuse me? Sheldon: She's my twin sister. She thinks she's funny, but frankly, I've never been able to see it. Missy: That's because you have no measurable sense of humor, Shelly. Sheldon: How exactly would one measure a sense of humor? A "humormometer?"