If you are writing it in a story, it would be:
Lord Fluffybottom's pants fell to the ground as he happily raised his glass and screamed, "Hail to the queen!" The entire room of diplomats gasped and stared at his rainbow striped underwear with a pink unicorn on the left leg.
But if you are writing it in a screenplay format it would be:
INT. PALACE - DINING ROOM - EVENING
Drunken Lord Fluffybottom stands to make a toast and does not notice his pants falling off. He is wearing rainbow striped unicorn underwear, at which the diplomats in the room gasp and stare.
Hail to the queen!
For video games and comic books there isn't a standard format. This is what I personally use for comic books:
Numbering is: scene.page.panel
Scene 1 Summary – Lord Fluffybottom's drinking catches up with him in the middle of the diplomatic banquet at the palace.
1.1.0 - Scene Title "A Toast!" (All scene titles should be in the same cursive font.) Exterior of the palace, evening, showing the arrival of expensive cars with diplomat flags/plates and the well-dressed diplomats emerging to enter the palace. Chauffeurs and uniformed guards also decorate the scene. This panel is the full page width and 1/3 of the page tall.
1.1.1 – Lord Fluffybottom is seated at a banquet table, with other diplomats beside him His cheeks are red and he is holding up a champagne flute which a waiter is refilling. On the left sits Lord Suchandsuch, who is also somewhat drunk and in the middle of a rambling speech, "...good lord, Limburger, on the Queen's birthday? Stilton, man, Stilton!" Left half of the page, middle third.
1.1.2 - Lord Fluffybottom is overcome with a sudden fit of patriotic ecstasy - he stands, his chair shooting back. His glass is raised and he shouts "Hail to the queen!" while Lord Suchandsuch blinks up at him through his monocle. Right half of the page, middle third.
1.1.3 - Lord Fluffybottom's trousers, alas, couldn't take all the excitement - they fall down around his gartered socks, revealing his rainbow striped boxers with a pink unicorn on one leg. Lord Suchandsuch now peers downward through the monocle and his mouth has fallen open a bit. Suchandsuch mutters "I say, dear boy, I believe... you may have had a bit of a wardrobe malfunction..." Left third of the page, bottom third.
And for a video game, you may have the player making a dialogue choice. Again, this is the system I personally use:
Numbering: 30 is a plot milestone, these can be universal for a game or specific to a character or quest; they are done by 10s so there is room to insert things in between if necessary. 1 is the first in a sequence of dialogues and/or actions from a character. R is Root, meaning that the dialogue does not depend on any factors besides the plot milestone. A, B, etc. are the player's dialogue choice that the player is responding to. Q is a condition that the game checks to see if it is true.
FLUFFYBOTTOM 30.1R Lord Fluffybottom is holding a glass. When the player approaches, He raises his glass, shouts "Hail to the queen!" and his trousers fall down with a comical sound effect. His boxers are revealed to be rainbow striped with a pink unicorn. Player's response choices: A. Pretend you saw nothing and walk away. B. Point and laugh. C. Flirtatious Compliment.
FLUFFYBOTTOM 30.2A A waiter places a folding screen in front of Lord Fluffybottom, who then fixes his pants. The waiter removes the screen.
FLUFFYBOTTOM 30.2B FluffybottomRep -5 Fluffybottom notices his trousers, says "Ohdearohdearohdear..." and pulls them back up.
FLUFFYBOTTOM 30.2C FluffybottomRep +5 Flufflybottom laughs sheepishly, rubbing the back of his head. "Eheh, I believe my patriotic fervor may have gotten the better of my suspenders!" Then he leans forward and adds, "(whisper)Come to my room some time if you want to see my My Little Pony collection! (wink)"