When Sheldon crashes in on Stuart (Kevin Sussman) and Penny's date, he ends up arguing with Stuart on comic books until they put Penny and Stuart's chances of getting lucky to sleep.
Penny brings in Chinese for the guys and hangs out in her sweats. Don't worry, for now Wolowitz still thinks she looks ravishing. It's only when the new neighbor shows up does Penny need to step it up.
Penny and Leonard discover paint in Sheldon's spot on the couch after the gang plays paintball in next week's episode of The Big Bang Theory, "The Cushion Saturation."
Sheldon: I'll have a diet Coke. Penny: Can you please order a cocktail? I need to practice mixing drinks. Sheldon: Fine... I'll have a virgin Cuba Libre. Penny: That's... rum and Coke without the rum. Sheldon: Yes, and would you make it diet?