"The Nerdvana Annihilation" is an episode of The Big Bang Theory that first aired on April 28, 2008. Directed by Mark Cendrowski. Teleplay by Stephen Engel and Steven Molaro based on a story by Bill Prady.

Howard, Leonard, Raj and Sheldon each contributed $200 to buy the time machine from The Time Machine (1960). They thought it was some kind of miniature, but it's the actual full-size prop with a seat for a human actor to sit on. The prop is delivered to the lobby of the apartment building, but now the guys have a tough time getting it up to Apartment 4A because the elevator doesn't work.^note The question of whether it would even fit in the elevator is of course moot.

So they start going up the stairs with it, with Howard and Raj pushing from below and Leonard and Sheldon pulling from above. Unfortunately Penny's running late to work and the stairs are blocked with what is essentially a toy. Penny goes to the roof and somehow gets to an adjacent building. Later she recounts her ordeal to the guys:

Penny also calls the guys pathetic for wasting their lives with "stupid toys and costumes and comic books" and now the Time Machine prop. Howard, Raj and Sheldon continue playing with the prop, but Leonard takes what Penny said to heart and resolves to sell off his collectibles.

The next day, Leonard has his collectibles all boxed up and ready to take to a buyer when Penny shows up and apologizes, and takes a markedly different opinion of the items Leonard intends to sell off. But Leonard is resolute... until a good-looking tall guy (Andrew Walker) shows up for another round of sex with Penny.

Tropes

• Answer Cut: Sheldon wonders why nobody bid on the time machine. One cut later, and we see it's life sized.
• Artistic License – History: Howard thinks that on March 10, 1876, they can knock on Alexander Graham Bell's door and be greeted by his wife, but Bell was single until July of the following year. Plus there's also the problem that if the time machine did work as depicted in the movie, they would still have to travel from Pasadena to Boston, a journey that back then could not have been made in a single day.
• Comically Small Bribe: Sulking over Penny denigrating his love for toys and comic books, Leonard boxes up all his collectibles to take them to the comic book store and his friends start offering him only pettily meager amounts such as only half of his share of the time machine or in Howard and Raj's cases foreign currencies (bar mitzvah bonds and rupees). While Leonard never mentions how much Larry offered, Leonard did say it was a fair price and he rejects his three friends' offers to match it most likely on the basis they don't have enough money to do so.
• Dirty Coward: When getting approached by Morlocks the second time, Sheldon begs the Morlocks to eat Leonard instead.
• Dream Within a Dream: The Stinger is Sheldon dreaming that he used the time machine to travel to the future, where he's attacked by Morlocks. He wakes up and tells Leonard about it, and Leonard informs him that he called movers to take away the machine... which turn out to be Morlocks. Sheldon then wakes up for real.
• Flipping the Bird: Alluded to during the gang's attempts to get the time machine up the stairs:
  Raj: Sheldon, if my fingers ever work again, I've got a job for the middle one!
• Heroic BSoD: Leonard after Penny's scathing rant, to the point he was almost going to sell all of his collectibles without even giving thought to just giving them to his friends who were outright offering him money for those (albeit he wasn't impressed with their offers).
• Hypocrite: Sheldon angrily calls Penny one when Leonard wants to sell all of his collectibles because of what she said the previous day, pointing out that for her entire rant about how "grownups don't play with toys", she is also a collector of various girly toys and collectibles.
• Insane Troll Logic: Leonard wants to hurt Sheldon and punch him when Sheldon goes to insult him some more for the fact Penny's not in the mood to have sex with Leonard. Sheldon points out inflicting an attack on him would be meaningless because it won't change the past, when it would really change his future for the worse.
• Irony: Penny lost an entire day's worth of wages because of a time machine.
• It's All About Me: Leonard says he isn't going to sell any of his stuff to any of his friends, because if he does then the other two will be mad at him for not giving it to them. Sheldon immediately says who cares about that as long as Leonard gives it to him.
• Product Delivery Ordeal: In this episode, the guys purchase what they believe to be a miniature time machine replica, realizing too late that the product is actually a massive prop. Once the item arrives, they struggle to figure out a way to take it to Leonard and Sheldon's apartment, since the building's lift is broken. With no other choice, they slowly and painfully push the machine up the stairs but end up blocking the stairwell. This in turn prevents Penny from arriving at work in time, setting the episode's conflict in motion.
• "The Reason You Suck" Speech:
  • Penny gave one to the guys for holding on to collectibles since it cost her a day's pay at work. She later admits that she didn't mean it, and was just in a bad mood.
  • Sheldon gives her one near the end, calling her a hypocrite for keeping collectibles at her place as well.
• Shout-Out to Elton John: Penny says the time machine prop "looks like something Elton John would drive through the Everglades." Of course Sheldon points it "would be worse than useless in a swamp."
• Time Travel Tropes: Several are discussed:
  • Fantastic Time Management: Leonard jokes that he could use the time machine to drop Penny off at work yesterday.
  • Field Trip to the Past: Leonard plans to travel back in time to see Alexander Graham Bell invent the telephone.
  • Grandfather Paradox: Sheldon explains it when Leonard says he wants to go back in time to stop himself from buying the time machine.
  • Our Time Travel Is Different: The gang does a humorous impression of the "Videocassette Time Travel" variation.
  • Time and Relative Dimensions in Space: Raj mentions Leonard would logically end up in 1876 Pasadena, not in Alexander Graham Bell's Boston lab. (The show does not mention this, but Sheldon would probably be horrified to learn that present-day Pasadena was the site of a tuberculosis colony in 1876. It's also worth mentioning that they're not on the ground floor, and their building presumably wasn't built yet in 1876.)
  • Time-Travel Romance: When Leonard says that girls like Penny don't go for guys with time machines, Sheldon points out examples of this trope.
• Undercrank: Parodied when Leonard plays in the time machine and the others run around as if sped up.
• You Shall Not Pass!: Sheldon at Leonard.