It's not the funniest of Goon Shows (more plotless than most, which is saying a lot for a Goon Show...) and is filled with British references that will likely go over the heads of American audience (not to mention all the catchphrases that were known and beloved by the Goon fans), but this is a legendary broadcast worth seeing regardless, since even if it's not the funniest, it's great fun -- and historic. And the audience in the theater is having an uproarious time. What's also a joy is watching how much fun the three actors are all having, most especially getting the chance to work together again -- particularly Peter Sellers, who by then was probably at the height of his movie career. It's easy to see from his beaming face throughout why he said in the clip used in that special that The Goon Show was the most fun he had working in his career.
(To make the reunion complete, they even brought back the show's two musical performers, singer Ray Ellington and harmonica player Max Geldray, who always played for the program's two music interludes.)
Before they get into the show itself, there is a bit of a warm-up with Harry Secombe singing a number accompanied by piano -- and Peter Sellers on timpani. This is followed by Sellers dramatically whistling the "To be or not to be" soliloquy from Hamlet.
Keep in mind that this was written and performed for radio -- so at times, it might be fun to close your eyes and listen to the lunacy as intended. But because of the occasion, getting the chance to watch is the biggest treat of all.