Leonard: So, Mom, you haven't seen Penny since we got engaged.
Penny: Yeah, let me show you the ring.
Beverly Hofstadter: Oh, lovely. Must have been very expensive.
Sheldon: Oh, no, not at all. No, we found a place online that repurposes diamond drill bits.
Leonard: We did not. That's not true. Can I speak to you alone for a second?
Sheldon: Oh, sure.
Leonard: It came from Tiffany's.
Sheldon: You mean the box, right?
Leonard: Keep walking!