Wizards of the Coast had planned to produce a Dungeons & Dragons television show inspired by one of its most unique campaign settings. Back in 2002, Wizards of the Coast filed a trademark for Spelljammer, the space fantasy setting involving magic ships sailing through a sea of gas-like phlogiston to reach worlds encased in glass spheres. Wizards of the Coast filed the trademark "for entertainment services in the nature of an on-going television series and production of motion pictures." The old trademark was eventually abandoned in 2004. The old trademark came to light in a forum post at The Piazza, a D&D focused site.
Interestingly, this was the second attempt at making Spelljammer into a live-action project. In the early 1990s, TSR almost released a board game called Wildspace that used Spelljammer ships and other elements. The board game came with a VHS that showed a group of live-action adventurers undertaking the same quest as players, which served as a tutorial and primer for the board game itself. Wildspace would have been a sequel to Dragon Strike, a similar board game but using traditional fantasy tropes. TSR cancelled the project before it entered production, although a teaser for the game (and the terrible live-action VHS) still exists on the Internet and can be seen below.
While a live action Spelljammer TV show or movie never made it into production, the space fantasy setting remains alive in the hearts of fans. Wizards of the Coast has all but confirmed some sort of revival of the Spelljammer setting, as a playtest released last year featured rules for several of the alien races found in that setting. Whether that's a full on revival of the Spelljammer setting or a part of some sort of wider multiverse book. One of the D&D design studio's focuses over the next couple of years is to bring more campaign settings for players to explore. The D&D design team is also working on a retooling of the core rules, with a planned release in 2024. A live-action Dungeons & Dragons movie (which to our knowledge features no spelljammer ships) will also be released in 2023.