The Beach Boys on Shindig, December 23, 1964 (taped 12/14) - Papa Oom Mow Mow, Johnny B. Goode
Two covers (originally by the Rivingtons and Chuck Berry) that they obviously enjoyed on this pre-Christmas show. The Shindig dancers joined them on the second song.
Brian looked so happy there.
The reason the thread title mentions when this was taped is that the morning of the 23rd, just hours before this show was broadcast, Brian suffered what's usually described as a nervous breakdown on a flight from LA to Houston. He was worn out and had suffered a panic attack on a flight to Australia in November. After he reached Australia he called his girlfriend, Marilyn, and proposed, and they were married December 7. Articles I found disagreed on whether he was able to appear with the band that night in Houston, but this was the breakdown that caused him to stop touring for years. No one watching Shindig that night would've suspected how much stress he was under.
https://www.houstonpress.com/music/shored-up-6564082
https://faroutmagazine.co.uk/beach-boy-brian-wilson-flight-changed-his-life/