"The Cruciferous Vegetable Amplification" is the second episode of the fourth season of the American sitcom The Big Bang Theory. This episode first aired on Thursday, September 30, 2010.
Sheldon works out that he won't live long enough to download his consciousness into a robot body. Elsewhere, Penny is low on funds to repay Leonard back for the Indian food, the pizza, the Thai food, the tank of gas, the frozen yogurt and her rent meaning she owes over $1,400. On the night Sheldon announces cruciferous vegetable night, and the next night where he introduces his MVPD, Howard and Raj make jokes about Penny living a free life without money, which only annoys Penny. Finally, she scares them off making jokes forever by sarcastically offering to sell her underwear for $1,400. They initially laugh it off, but immediately start to think it over with intrigued looks on their faces.
Sheldon determines that his best estimate for his life expectancy will cause him to miss, by only a few years, "the singularity... when man will be able to transfer his consciousness into machines, and achieve immortality". He therefore changes his diet and starts to exercise in hopes of extending his life expectancy. Unfortunately for Sheldon, he wakes up in the middle of the night with pain in his stomach, causing the concerned Leonard to take him to the hospital. However, Sheldon breaks wind before they exit the apartment, and he realizes that it must have been the Brussels sprouts where a disgusted Leonard heads back to bed. The next day, Sheldon join Penny for jogging exercise, and after warming up, they begin to jog down the stairs, but he tumbles down the stairs before he accidentally breaks wind at Penny. Afterwards, Sheldon decides on an alternate plan to extend his life expectancy.
He builds a robotic replication of himself which he calls a "Mobile Virtual Presence Device" (MVPD) that would go through all the hazards of life that Sheldon would otherwise have to experience while he stays behind in a "secure, undisclosed location" (his room). The MVPD has a monitor showing Sheldon's face in real-time (or any other image that he wants to display at that moment), speakers so his voice can be heard, and a microphone and camera to allow him to see and hear in his "secure, undisclosed location" (his bedroom) what is happening at the MVPD's location. Sheldon can then react to the situation as if he was present (to the point of enforcing the rule that nobody sits on "his spot" on the sofa). The monitor sits on top of a fixture covered with the exact same clothing that Sheldon is wearing that day. The MVPD has wheels which give it mobility and comes with an override switch so if anybody turns the MVPD off, Sheldon can override and turn the monitor back on.
The guys dismiss the MVPD as a stunt (Penny calls it "Shelbot") and try to convince Sheldon to drop the idea, but he persists and proceeds to cite Section 74c of The Roommate Agreement requiring Leonard to assist him (by providing him transportation) "in the event one of [the roommates] becomes a robot." Leonard therefore has no choice but to take the MVPD to work, though he regrets it, following Sheldon's new games. Leonard turns off the device, but Sheldon turns back on the device with the override switch, startling Leonard, causing him to nearly crash and tells Sheldon that he was almost killed, where Sheldon responds that he is safe and sound in bed. At work, only Raj is able to open the office door for the MVPD when Leonard refuses. Later, Leonard has to take the MVPD to Penny's restaurant for dinner.
At the restaurant, Sheldon's MVPD spots Steve Wozniak at a nearby table so he sends the MVPD over to meet Woz, telling him that he has a vintage Apple II computer, to which Wozniak says that if he had the Apple II there he would sign it. Sheldon then takes his Apple II and rushes out of the apartment, but trips and falls down the stairs, accidentally destroying the Apple II.
Later, Sheldon's MPVD goes to Penny's apartment door to help him fall asleep after the aftermath of falling down the stairs and the accidental demise of his Apple II. He wants her to sing him a song to go to sleep by. At first she is reluctant, but he soon convinces her to do so. Sheldon plays "Soft Kitty" on his recorder while Penny sings.
- It is revealed in this episode that Penny jogs in her spare time, where it was learned from Raj because he was watching her with his binoculars from his window.
- The title references the cruciferous vegetables that Sheldon adds to his diet, only it caused him to majorly break wind.