MASH 4077 on a whole. The reason MacArthur is visiting the camp is because the work of the staff has achieved the recognition of the unit being named the most impressive medical station in Korea.
Henry: That's north, south, east or west. We're the MASH that is the best.
When Henry asks for quiet from the camp, it's an Epic Fail. When Radar does it, the effect is instantaneous. Hawkeye and Trapper lampshade the ability.
Berserk Button: Given the historical allusion for it, which for the time MASH is set in would only be recent memory, it's no wonder Hawkeye is furious with Frank's decision to start burning books that only the major would deem as filthy material.
Hawkeye: Frank. You burn one more book, I'm gonna give you a dancing lesson in the minefield. Now, knock it off, gnat brain!
Big "SHUT UP!": Well, what would you do if you had Frank Burns giving orders loudly through a megaphone extremely close to your head?
Henry: Well, that's just what I was thinking. It'd be a real eye-popper.
Book Burning: Hawkeye and Trapper find Frank doing this, with the major explaining he's doing it because he doesn't want MacArthur to know about any filthy material the camp is reading. After making a dark Historical In-Joke to insult him, they examine the books he is about to destroy.
When Colonel Whiteman exclaims the word "Lunch", majority of the main characters take it to mean he's calling for a break. He is instead continuing the iteration the general's schedule.
Klinger fails to realise the reason for Henry Blake calling him to the office is because he wants him to forgo his prove-he's-crazy scheme and get into a military uniform for the duration of MacArthur's visit.
Cut His Heart Out with a Spoon: After Hawkeye has already given him a strong death threat for his Book Burning, Frank pushes his button further by ordering him and Trapper to clean up the Swamp, otherwise he'll do it himself. Hawkeye angrily retaliates with this gem.
Hawkeye: You touch one dirty sock, you remove one layer of crud, you kill one cockroach, Frank, and I will personally grind you into a fine powder and sprinkle you on MacArthur's oatmeal.
Trapper: What he said.
Flat Joy: Hawkeye and Trapper's reaction when the official announcement of MacArthur's visit is made.
Foreshadowing: Colonel Whiteman strongly advises Henry not to have the same man on sentry duty when the General arrives. Upon being told by Radar that the current man on duty is Klinger, Henry promises that Klinger won't be seen.
Genius Bonus: Margaret tells Frank that her father fought with MacArthur against "the Huks...a rebellious native tribe." The Hukbalahap Rebellion was staged by a guerrilla army that had originally fought against the Japanese occupation of the Philippines in WWII. After the war ended, they decided they were tired of being exploited by wealthy landowners and took up armed resistance. The Philippine government brutally put down the rebellion with assistance from the CIA, who were always happy to assist quashing any movement that looked remotely like socialism.
Jaw Drop: Radar when he gets the important message on the phone.
Kick the Dog: While Henry finds Spaulding's first song catchy, Frank tells the guitar player he's not in the least bit clever.
No Name Given: Before this episode, Margaret's dad was always referred to as "Margaret's dad" or "the colonel". Here, he is given the name Howitzer Al Houlihan, a name that actually stays with the character for the rest of the series.
The Reveal: About three and a half minutes into the episode, it is unveiled what the important telephone call was about. The 4077th is going to be paid a visit by none other than General Douglas MacArthur.
Running Gag: Klinger is in a different dress every time he appears.
"Shaggy Dog" Story: At the end of the episode, MacArthur just passes on straight through the camp and continues on down the road instead of making the scheduled stop, which renders all of the camp's preparations meaningless.
Shout-Out: Hawkeye and Trapper introduce themselves to the fake General MacArthur at the rehearsal as Sodom and Gomorrah.