When Howard's brother finds out about Howard and the robot arm, he says "Because that's all you need". This was also said in the episode where Howard got 'stuck' in the robot arm, The Robotic Manipulation (2010), as the answer to the question why he only built the arm and not the rest of the robot.
Kevin Smith asks Penny to come and read for a part in 'Clerks 3'. At the time when this episode was produced, Clerks III (2022) was actually in pre-production and aiming for a 2016 release, but it got canceled because Jeff Anderson (who plays Randall in the Clerks series) didn't like the script. Smith and Anderson have since rewritten the script and put the film back in production, but it would not be released until 2022, three years after the The Big Bang Theory ended, and without Penny/Kaley Cuoco.
At the beginning of the episode, Howard and Raj are seen arguing over the pronunciation of GIF. Howard and Leonard argue that it is "gif" because the g stands for graphics, while Raj argues that it is pronounced "jif" because so says the creator of it. In fact, Raj is actually correct in its pronunciation. The creator, Steve Wilhite, has publicly stated multiple times that "jif" is the only acceptable pronunciation. He and his team wanted to pay homage to the Jif peanut butter brand by stating "choosy programmers choose jif", a play on Jif's slogan "choosy moms choose Jif".