Howard has a hard time dealing with being in space, but an even harder time coming back down to Earth. Raj begins working through his mutism, starting up a relationship with a timid girl named Lucy. Penny tells Leonard she loves him, startling them both. Leonard is selected to go on a research expedition directed by Stephen Hawking.
Tropes in The Big Bang Theory Season Six
- Batman Gambit: Bernadette's plan for her and the girls to ditch work and go to Disneyland for princess makeovers. Turns out she knew Howard would like seeing her dressed as Cinderella.
- Cut Short: In-Universe, the Syfy show Alphas, which leaves Sheldon dissatisfied with the lack of closure.
- Dude, Where's My Respect?: Howard is disappointed that there was little fanfare for going into space.
- Felony Misdemeanor: In "The Spoiler Alert Segmentation", Leonard and Sheldon get into an argument over the latter spoiling Dumbledore's death in Harry Potter and the Half-Blood Prince when Leonard hasn't read that far yet, which culminates in Leonard declaring that he's moving in with Penny and storming out. Sheldon stops Leonard, like he's about to apologize... Then blurts out that Dobby dies in Deathly Hallows.
- Geeky Turn-On: Penny surprised herself at how attractive Leonard became when showing off his holograms.
- Then, he almost blows it by referring to Magneto when he shows her an electromagnet.
- Hypocritical Humor: While Amy and Bernadette talk to female students about how as women they are expected to just care about their looks rather than their minds, a Reveal Shot shows they are at Disneyland, having just gotten a princess makeover, and Amy is applying makeup. Penny gives them a dirty look.
- Mad Scientist: Referenced by Arthur Jefferies/Professor Proton (Bob Newhart) regarding Sheldon.Arthur Jefferies: Is uh, is he dangerous?Leonard: Actually he's a genius.Sheldon: I am.Arthur Jefferies: That uh, that doesn't answer my question.
- Master of the Mixed Message: Acknowledged by Penny in her relationship with Leonard, but she hated herself for doing so.
- Mining For Cookies: Invoked in "The Re-Entry Minimization". When Penny complains about playing a made-up game, Sheldon counters that "all games are made up. They are not found in nature. No one digs in the ground and finds a rich vein of Rock'em Sock'em Robots."
- Not So Different: In "The Higgs Boson Observation" Amy gets concerned that Sheldon hires Alex, an attractive female grad student, as an assistant. They go to his office and Amy immediately starts rubbing various materials and licking the stapler to "spread her scent" and mark her territory, which Penny derides as silly. Later in the episode, after seeing Alex and Leonard acting very friendly with each other, Penny starts acting a lot more possessive of Leonard, even dragging him to the bedroom randomly, essentially doing the same "mark your territory" that Amy was doing.
- Sexy Spectacles: Penny wears glasses to make herself look smarter, which turns on Leonard.
- Take That!: To Heroes. According to Sheldon, the quality decreased over time.
- Puppy-Dog Eyes: Leonard saved himself a break-up because of his. Subsequently parodied by Amy and Bernadette.
- Wham Line: Sheldon saying "It's a possibility" with regards to him and Amy becoming intimate threw Penny for a loop, clawing Leonard's arm afterwards.
- Penny telling Leonard that she loves him, which she had never done before and caught not only herself and Leonard, but the audience by surprise.
- In the finale, Penny checks on Raj after his breakup. He's so distraught that he pours out his heart to her and reveals that he's completely sober.
- Yank the Dog's Chain: Raj finally gets a girlfriend, but she gets overwhelmed and has to break up with him.