The Classified Materials Turbulence

Summary
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.

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