When a character enters an episode midway through the story, typically, the first thing they say is, "What is going on?" or "Would someone mind telling me what's going on?" or some other variation on this phrase.
Then the other characters typically give a quick summary of the story so far, or there is a quick cut away to another scene for a bit or simply quick fade in/fade out back to the characters that implies they had just finished giving a detailed briefing of the situation. If it's the audience who is also wondering what's going on, be prepared for an Info Dump.
The polar opposite is Let Me Get This Straight....
- The Princess Bride, after Westley is revived from being Only Mostly Dead:
Westley: Who are you? Are we enemies? Why am I on this wall? Where is Buttercup?
- Blazing Saddles, when Taggert arrives at the railroad worksite to find all his foremen singing "Camptown Ladies":
Taggert: What in the wide, wide world o' sports is a-goin' on here?!
- In Mary Poppins, Mary, Bert, the two children, some other chimney sweeps and Mrs. Banks' suffragette society are dancing through Mr. Banks' house when he comes in. His reaction is to yell "What's all this?" which becomes a part of the song.
- Done so often by Mr. Belding on Saved by the Bell that "Hey hey hey, what is going on here?" became his Catch-Phrase (and is worth two sips in the Drinking Game).
- Given the incredibly serial nature of 24, this trope pops up a lot, mostly after Jack or CTU has uncovered a new threat, the President asks to be "brought up to speed".
- This happens so often, in fact, that certain characters (Tim Woods, amongst others) were seemingly created for the sole purpose of filling the audience - and the President - in on the details of what just happened.
- Parodied in the first season finale of Drawn Together, where Xandir would shout this catch-phrase out whenever the narrator introduced a Shocking Swerve to the contest, which seemed to happen once every five minutes.
- Because said bit is viewed from outside the house to hide the exact emotion of the one yelling the phrase, it might have been a spoof of promos (which were, at the time, being played on the network constantly) for Spike TV's The Joe Schmo Show, a fake reality show that one contestant is led to believe is real. The show is also alluded to later in the same episode.
- General Hammond from Stargate SG-1 often will enter a strange scene with "What is going on here?!" (sometimes with "the hell" thrown in), or occasionally "What the hell are you/do you think you're doing?!"
Jack O'Neill: [whilst hitting golf balls through the Stargate] ...In the middle of my backswing?!
- In the Supernatural episode "All Hell Breaks Loose, Part Two" (S02, Ep22) after Sam is resurrected, Sam asks, "Dean... what happened to me?" This leads Dean and Sam to exchange information about what happened in the previous episode, although Dean let's Sam believe he was merely badly wounded and Bobby patched him up.
- The Defenders (2017): Given that Jessica Jones and Luke Cage are newcomers to this war against the Hand that Matt Murdock and Danny Rand have already been engaged in at some capacity in the past, they often are left having to ask these sorts of questions.
- The Powerpuff Girls: In "Mommy Fearest", as Professor Utonium walks into the house to find the girls and Sedusa battling each other in the living room.
Professor: Oh, girls, I'm back from the sto—OOOORE?! (drops his groceries) What's going on here?!
- Young Justice has Superboy expressing this to the Forever People after learning more and more about the New Gods, but not enough to get a clear picture.
Superboy: Look, I've been remarkably patient. Y'know, for me. What is going on?