Raj And Howard Fight (And Bounce) It Out On The Big Bang Theory

Also, Leonard reflects on his perceived lack of accomplishments in "The Celebration Reverberation."

The fight's still on between Howard and Raj—much to their friends' chagrin!

In the latest episode of The Big Bang Theory, "The Celebration Reverberation," which airs on Thursday, Dec. 14 at 8/7c on CBS and CBS All Access, Howard ( Simon Helberg) and Raj ( Kunal Nayyar) are barely on speaking terms and nearly come to blows in a bounce house at Halley's birthday party.

STREAM: Full Episodes Of The Big Bang Theory On CBS All Access

Speaking of birthdays, Sheldon ( Jim Parsons) plans a celebration for Amy ( Mayim Bialik). Will the couple honor their birthday tradition?

Check out a preview of "The Celebration Reverberation" in the video above.

While his friends are working (bouncing?) out their issues, Leonard ( Johnny Galecki) reevaluates his life after receiving a Christmas letter from his brother.

Will Raj and Howard work out their differences?

And can Leonard pull himself out of the self-doubt spiral?

Watch all-new episodes of The Big Bang Theory on Thursdays at 8/7c on CBS and CBS All Access.