A stage play by Richard George that's extremely faithful to the book; Dahl approved of it.
A BBC Radio 4 adaptation (The Eighties). (Also, the novel has at least five different audiobook versions.)
A 1985 video game for the ZX Spectrum.
Roald Dahl's Willy Wonka, a 2005 stage musical. It used the 1971 film's songs and added new numbers by Leslie Bricusse, the film's lyricist, but was a closer match to the book plotwise. Productions were mostly mounted by regional/amateur companies before the title was retired by the licenser in 2014 (owing to the 2013 musical superseding it).
The 2005 film had several tie-in video games.
A theme park ride at the U.K. park Alton Towers.
Defictionalization: Wonka is actually an actual brand of candy that started in 1971 (after the first film adaptation). It is currently owned by Nestlé.
In fact, Quaker Oats gave a ton of money to the production and then changed the name of their upcoming candy line to Wonka, which is also the reason for the title change.
Most of the candy as well. Everlasting Gobstoppers don't last forever, sadly.
Ironically, for a candy company named after a chocolate factory, they don't make many chocolate products.
Also ironically, for a brand of candy made by a British company based on an Book from a British writer, they seem much more popular in America.
Nestlé supplied all of the edible prop candy for the 2005 film, because they had bought the Wonka brand by then.
Now there also is an inflatable blueberry suit (obviously NSFW), to imitate Violet's transformation .
What Could Have Been: The original concept for the story didn't even have any children in it! After that, there were multiple drafts, each with different numbers of children (anywhere from five up to thirty) with different personalities and fates (explained below). The general plot was different too: in an early draft the factory tours were a weekly event, Willy Wonka had a son called Freddie, and the story ended with Charlie getting his own chocolate shop.
Early concepts for children included Miranda Mary Piker, who was a school-obsessed swot; and Marvin Prune, who was a very conceited boy. Also — and this is absolutely true — Mike Teavee's original name was Herpes Trout.
The Oompa-Loompas' original name was the Whipple-Scrumpets.
Martin Scorsese was reportedly considered for the director's job. Marilyn Manson was rumored to be his choice for Wonka, and Manson did campaign for it in any case.
Frank Oz was also attached to the director's chair before Burton took over.
Another director considered was Gary Ross.
Michael Keaton was the original choice to play Wonka.
Before Burton was signed on, other rumored Wonkas ranged from Robin Williams to Will Smith to Nicolas Cage. And once he was, he considered Christopher Walken before going with Depp. Brad Pitt wanted to play the role of Wonka as well, but was turned down.
Michael Jackson, according to his brother Jermaine's book You Are Not Alone, was all set to campaign for the Wonka role — and then he was charged of child molestation for the second time in his career and had to give up that idea for good. Colleague/producer Marc Schaffel goes further with this, claiming that Michael actually wrote a whole soundtrack for the movie and submitted it to Warner Bros. in 2000, figuring that they would give him the lead on the basis of it. But though executives loved it, they were not comfortable casting him as Willy Wonka, and offered to find another role in the film for him in exchange for the soundtrack. Michael was too dead set on the lead role to allow this, so it fell through. A few weeks before the movie hit theaters in July 2005, Jackson had been declared not guilty of the charges after a high-profile trial, so the unintentional, superficial resemblances between him and Depp's take on Wonka were brought up in many reviews and commentaries.
SamNeill auditioned for the role of Mr. Salt, but Burton said he wanted Johnny Depp to be the only name actor in the movie. (As for Christopher Lee's appearance, that's more Creator Thumbprint.)
Gregory Peck was first offered the role of Grandpa Joe, and he told Warner Brothers that he'd consider it. Sadly, he died before he could give his answer, but his family has revealed he was very eager to play the part. The only reason he didn't say yes right away was because he was afraid it would make him seem desperate and cause the studio to give him a lower paycheck.
As discussed in this article, director Sam Mendes first tried to get the stage rights to the novel in the late 1980s. He tried again at the Turn of the Millennium, but the rights were with Warner Bros. by then, and they were busy with what became the 2005 film. It was another two years after its release before the go-ahead was given for a new stage adaptation. From there...
The show went through fifty drafts over a five-year period!
Before going with the conceit of adult actors in trick costumes (ala how Lord Farquaad was handled in the stage version of Shrek) to play the Oompa-Loompas, the creators considered either using puppets or casting children in the roles.
According to Douglas Hodge (who originated the role of Willy Wonka), "It Must Be Believed to Be Seen" was almost a Cut Song, as the songwriters came up with a far more bombastic number to take its place. That song made it to the readthrough stage, but Hodge wasn't happy with it and wanted something cheekier...so the writers, who felt much the same way by that point, played "It Must Be Believed to Be Seen" for him, and with further tweaking, the song was back in the show.