What's the most unusual way you have seen someone receive notification of promotion?

In a BN TOC, GEN Milley was being briefed by the BN S2 about the COP. The SPC intel analyst began providing the enemy situation, composition, disposition, and SIGACTs in the event (JRTC DATE rotation) and GEN Milley was impressed. The S2 OIC mentioned that he was promotable, but waiting on points or some admin factor to get promoted to E-5. GEN Milley thereby promoted the SPC on the spot to SGT, and then told his aide something like: I know I can do that, go figure out the details and make sure this is followed-thru. That SGT's DOR is that day.

Mine!
While stationed in West Germany in the late 70's my company was on a FX and we were scheduled to convoy back to garrison on the day of my promotion.
The night before, I was ordered to report to the CO's tent.
I was thinking, " Oh sh*t! What did I do!"
As I walked into the tent, Top was calling "Attention to Orders!"
My First Sergeant and the company clerk stood by as the CO pinned my new rank on me.
When I cought up with the rest of my platoon at the canteen that night they all new about it and I was buying the next round of beers.
So, that's the story of how I walked into the old man's tent a private and came out a Spec4.
Never lived that down for the rest of my service!

At the time I was a Tsgt living in The Netherlands in off base housing. I got a phone call and was told to REPORT to the commander's office. When I walked in I saw the 1st Shirt, who happened to live next door to me, sitting in the corner. I report and the commander says at ease. He starts reading me my rights and I'm thinking to myself what is happening right now. He said tell me what happened at your house last night. Now I'm really confused because nothing happened at my house. The 1st Shirt says, wasn't your house damaged last night? Oh yeah, the wind blew our outside light globe down and it broke and I called housing already. So they go in on how it looks for the US military and Americans in general when I MSgt can't maintain his quarters. I don't even hear that part and start explaining that housing said that they would have a replacement tomorrow. Then they go in on a discussion I had with a neighbor about a patch of grass I forgot to cut. It is bad for a MSgt to get into public disputes with our Dutch allies. I'm thinking, are you FN kidding me? MSgt Williams what do you have to say for yourself. Wait, what? While you're at it fix your uniform and the shirt hands me MSgt shoulder boards. Speechless. I was more relieved that I wasn't in trouble than getting promoted. They got me.

In 1968 in Vietnam I was walking from my bunker on a rainy day. It was muddy. I just happened to look on the ground in the mud seeing this paper thing. I picked it up finding my name listed on it where I was promoted to SP4 days before. I never knew and no one told me.

In the late 1980's I was serving with the USAREUR Band and Chorus in Heidelberg, Germany. I was in charge of Chorus Operations (arranging tours and performances), new member auditions, and musical training for those new members of the Chorus -- as a SP4. I also performed with the Chorus, which had recently evolved into an accomplished show choir (singing with advanced choreography). Our company had irregular morning formations, since different groups of musicians were constantly on the road performing somewhere in Europe.

One morning the Chorus was sleeping in because we had gotten back from a concert late the night before. I was in bed when the admin clerk knocked on my door and told me to report to Top's office to be promoted. I reported, but requested that the promotion be delayed until our next full unit formation. He agreed.

Later that afternoon we were having a final dress rehearsal in the Heidelberg Stadthalle (historic city theater) for a special Broadway review show that involved both the Band and Chorus. During a break I was suddenly called up on stage, where I was promoted to SGT in front of the whole company, wearing a glitzy dancing costume. Luckily, I wasn't wearing the lacy nightgown ("I could have Danced all Night") or Mother Superior's nun's habit ("Climb Every Mountain") that I also wore for the show!

I was COW on submarine leaving homeport for a 6 mo Westpac when XO called for me to come topside. COW is VERY busy during maneuvering watch, so very unusual for that to happen. Worried that I had missed something in the preunderway checklist, I hauled ass topside where XO informed me that my wife needed me on the pier. I left boat and asked my wife (in a very exasperated tone) "WHAT?" She replied, "Congratulations Chief!"

The unusal way I saw an airman receieve his promotion notificztion, was at his NCO Leadership school graduation. He was handed his dipolma by the lead instructor, and the guest of honor (a four star) hand him his new stripee, to E6.

Here is a no shitter.
The company commander called and asked if we had anyone due for promotion to PFC and I gave him the name and the CO said he would be promoted. I called the private I and asked him if wanted to be promoted and he said yes. The Chief Warrant Officer I worked for was there and heard everything so I told the private - Please raise your right hand and the CWO said some shit that he had to replete and Chief said you are now a PFC. I told him to not pin it on until he got the orders.

During Desert Shield my squad leader came into the tent and just gave me my advancement orders. Best ceremony I ever had...lol.

I worked in personnel at Sheppard AFB, Texas, but not in the promotions shop (that came a few years later). I was walking across the parking lot when a window in the CBPO's second floor opened and the guy in charge of promotions yelled at me, "Brownie, you can buy that new car now!"
It was very early in the morning, so no one else heard him, and I acted properly surprised when the commander came around later to make it formal. The nice thing about working in personnel was that when I made Staff, Tech and Master, I knew about it before the commander did.