: Sheldon and Raj consider joining a research expedition in an abandoned salt mine to study dark matter. To test their endurance for the harsh, cramped conditions, they spend time in the university's underground steam tunnels.
: During their time underground, Raj and Sheldon discuss Star Trek: Voyager , Miley Cyrus, and the logic of Hannah Montana's secret identity. Production Credits Director : Mark Cendrowski
: To resolve their money issues, Leonard and Penny visit Howard and Bernadette. However, they quickly discover that the Wolowitzes’ own financial arrangement—where Bernadette earns significantly more and provides Howard with an "allowance"—is equally complicated. Notable Moments