The Big Bang Theory: The Spock Resonance

Leonard and Penny are shocked to learn that Sheldon had an engagement ring for Amy on a new episode of The Big Bang Theory, titled "The Spock Resonance," airs tonight on CBS.

While being interviewed for a documentary about Spock from "Star Trek," Sheldon struggles to suppress his emotions about his recent break-up with Amy. Also, Wolowitz and Bernadette butt heads over remodeling his childhood home.. Wil Wheaton, Adam Nimoy and Stephen Merchant guest star.

Below, check out three clips and a sneak preview.

"The Spock Resonance" episode of The Big Bang Theory airs tonight at 8:00-8:31 PM, ET/PT on CBS.