The Classified Materials Turbulence

Summary
The Classified Materials Turbulence is the twenty second episode of the second season of The Big Bang Theory. Howard has designed a special toilet for the International Space Station. He realises that it is going to malfunction and asks the guys to help him fix it. Stuart has another date with Penny and asks Leonard for advice. Leonard gives him bad advice and feels terrible about it. He tries to make things right but discovers that Penny said his name while kissing Stuart.

Extended Plot
The gang is at the comic book store, when the new comic book came in. Howard announces that he will treat them with new comic books to celebrate his new invention the "Wolowitz Zero-Gravity Waste Disposal System" (or Outer Space Toilet). Stuart approaches the gang and asks Leonard for some advice for his second date with Penny, Leonard says he will think of it. Howard tells Leonard if doesn't want to jeopardize his relationship with Stuart nor does he want Stuart to progress with Penny, he should tell Stuart to do exactly what Leonard has been doing for the past two years. Later, Leonard bumps into Penny when getting his mail, Penny seizes the opportunity to ask Leonard whether she dating Stuart bothers him. Leonard tells her it doesn't, although he was clearly lying, as Penny then proceeded to ask for advice on dating Stuart, but Leonard gave her useless advice. Stuart tried to call Leonard, but he was ignored as Leonard doesn't want to talk about Penny. Meanwhile, a distressed Howard tells the gang that he has made a fatal error in building his Outer Space Toilet. In an effort to help Howard, the gang has agreed to fix the Toilet. They bring an exact replica back to the apartment. Then, someone knocks on the door, and Leonard answers it. Stuart is at the door asking Leonard for last minute advices since they haven't been able to contact each other (Leonard has been ignoring Stuart). Leonard deliberately gives bad advice by drawing from what he has been trying on Penny. The next morning, Leonard was doing a coffee run for the gang and took the opportunity to stop by Penny's and ask about the date. But, when he asked Penny, she was very wound up and ended up slamming the door in Leonard's face. Leonard then leaves for the comic book store to meet Stuart, while the rest of the gang still fails to fix the Toilet. Leonard asked Stuart about the date, which he says it was great until the were making out, when Penny accidentally said Leonard's name. When Leonard leaved the store, he jumped in happiness. It seems Howard has found a solution and called the responsible parties to deploy the solution, he just hopes it works. In the final scene, we see that Howard's solution clearly did not work as the crew of the spaceship had to take "an unscheduled spacewalk".

Critics
"This is a disappointing episode in most ways but it is still entertaining." - The TV Critic's Review