Leonard: Sheldon, are you going to introduce us?
Sheldon: Oh, alright, this is Missy, Missy this is Leonard and Rajesh and you’ve already met Howard.
Missy: It’s nice to meet you.
Leonard: You too, swell, also.
Leonard: So, how do you two know each other.
Missy: Oh, 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: It’s because you have no measurable sense of humour, Shelly.
Sheldon: How exactly would one measure a sense of humour? A humourmometer?