Sheldon has to adjust to Penny and Leonard moving in together, and he's still dealing with his breakup. Bernadette tries to get Stuart to move out. Raj and Howard start a filk band.
- Continuity Nod / Call-Back: The Roommate Agreement makes an appearance. We also see the lawn furniture and decor from Season 3's "The Staircase Implementation".
- Disco Dan: Sheldon "reboots" his life back to 2003, back before he knew Leonard.
- Filk Song: Discussed. Raj's idea for the band is to cross folk music with sci-fi.
- Gag Echo: Emily complains to Raj that his song isn't danceable. He and Howard reject the argument, thinking that their audience won't care. In The Stinger they perform it at the comic book shop and Stuart has the exact same complaint as Emily.
- Gilligan Cut: Amy defends Sheldon, saying it's unfair to call him a weirdo. Cut to Sheldon sitting in an empty room and trying to recapture 2003.
- Hates Being Alone: Subverted. Sheldon didn't have any friends before Leonard, but he wasn't upset at losing anyone until Amy and Leonard left him.
- Shout-Out: To The Wizard of Oz and Pinocchio as Sheldon compares himself to the Tin Man (before the Evil Wizard gave him a heart) and Pinocchio before he was a real boy.
- Stylistic Suck: "Thor and Dr. Jones...One plays with lightning, the other plays with bones."
- Sure, Let's Go with That: Amy's response when Sheldon gives his interpretation of Pinocchio.
- Take That!: When Raj and Howard explain the concept of filk music, Stuart likes the sound of it, as it sounds like something he doesn't have to pay for.
- Terrible Interviewees Montage: Sheldon interviewing potential roommates. Inverted in that the interviewees are just fine, it's the interviewer that's the problem.
- Yoko Oh No: Howard accuses Raj of trying to break up the band, under Emily's influence.