The upcoming Harry Potter TV show from HBO will be able to address JK Rowling's source material in a far more extensive way than the movies ever did, but there's one moment in particular I'm hoping will make its on-screen debut.
As well as several book characters who were overlooked in the Harry Potter movies, there were countless scenes that were either drastically altered, shortened, or omitted altogether. Considering how long the show is expected to run, it's technically possible for pretty much everything from the books to be included in the story's new format.
I want to see Nearly Headless Nick's Deathday Party in HBO's show
John Cleese's Nearly Headless Nick is one of the most intriguing characters in the Harry Potter movies, but this iteration of Gryffindor's house ghost wasn't paid much attention when it came to his backstory. In the books, Nick has many more fascinating moments that expand the Wizarding World's ghost lore in a way that the movies just didn't find time to do. For example, when Chamber of Secrets was first published in 1998, the second book in the series featured a compelling sequence that showed how ghosts mark the day they died.
Nick's Deathday Party is a brilliant piece of Harry Potter worldbuilding that offers a unique glimpse into a specific area of the franchise canon. The scene was omitted from Steve Kloves' movie script, but I think it would make a great addition to HBO's TV adaptation. With season 1 expected to cover the events of the first Harry Potter book, it's reasonable to assume that season 2 will open the door to show the Deathday Party from the second novel.
Why the Chamber of Secrets movie ignored Nick's Deathday Party
Even with a runtime exceeding two-and-a-half hours, 2002's feature-length adaptation of Harry Potter and the Chamber of Secrets failed to explore every page of the relatively short book. This isn't an uncommon phenomenon, so it's understandable that the second movie in the series had to make cuts from the source material so that the end result wasn't too long.
As great as the Deathday scene is in the novel, I will admit that it would probably have stopped the movie's plot in its tracks. Worldbuilding is important, but it shouldn't be included if it causes pacing issues. Including Nick's macabre party would almost certainly have negatively disrupted the movie's tempo.
However, the adaptation that HBO is currently working on will have the added freedom of unfolding in a different format. The episodic nature of TV means the Wizarding World can be delved into more thoroughly without needing to worry about addressing everything from the books in under three hours per installment. The Deathday Party will surely be a beneficiary of this fact, as will other scenes that have been previously unadapted by the Harry Potter movie franchise.