- Howard Wolowitz: Engineers are just as smart as physicists.
- Sheldon Cooper: [offended gasp] You take that back!
- Leonard Hofstadter: Why are you going to so much trouble to prove you're smarter than Wolowitz?
- Sheldon Cooper: Oh, it's no trouble. It's actually a pleasure.
- Sheldon Cooper: [Knock knock knock] Mrs. Davis?
- [knock knock knock]
- Sheldon Cooper: Guess who?
- Janine Davis: Dr. Cooper?
- Sheldon Cooper: [Knock knock knock] That's right. Good job.
- Sheldon Cooper: You just shot your spit in my mouth!
- Howard Wolowitz: Is that going to be on the test? Because I don't think I can do it again.
- Howard Wolowitz: Which Archimedean solid has 20 regular triangular faces, 30 square faces, 12 pentagonal faces, 60 vertices and 120 edges?
- Leonard Hofstadter, Sheldon Cooper, Raj Koothrappali: The Rhombicosidodecahedron!
- Sheldon Cooper: The correct animal for inter-species super soldier is koala. You would wind up with an army so cute, it couldn't be attacked.
- Bernadette Rostenkowski: Okay, what are the potential side effects of our erectile dysfunction drug?
- Penny: Headaches, dizziness, and nausea.
- Bernadette Rostenkowski: Yes.
- Penny: Those are also the side effects of having a 75-year-old man with an erection climb on top of you.