Wild Sheep Chase is a great one for introducing people into D&D. A very silly one shot.

It’s first combat is quite difficult though and tends to blow out the timings when there are first time players.

Edit: oh, old post.

Everyone is John

There’s only one character to play: John, who is an ordinary office worker suffering from multiple personality disorder.
Each player plays one of the personalities, with their own stats and predefined (conflicting) goals. They are free to play “characters” from any setting or era.
In situations that are stressful to John, a competing dice roll determines which player takes over.
The other players can still talk and comment, and John will hear them argue inside his head.

A wild sheep chase

This is hard one because most of the one shots are just awful as they rarely include any guidance to how to run them in short of time. At least every one shot should include a guidance of how and which parts to leave out when time is running out.

So the best ones are usually systems designed for one shots without separate scenarios but assuming you are asking about those the most palatable one has been DnD 5e adventure Sarah of the Yellowcrest Manor from Candlekeep mysteries. The middle part can be pretty much skipped if the time is limited, there is at least some guidance on how to run it and the end dungeon is short and sweet.

Any of Grant Howitt’s single-page RPGs, great if you just need something fun at short notice

Alice is missing and The space between us, the latter being borderline LARP.

Both games are pretty intense with a huge bleed potential making them memorable experience.