For anyone in need of a quick Tree House refresher, the series follows siblings Jack and Annie as they time travel with the help of their, wait for it, magical tree house. It's kind of like The Magic School Bus, but without a chaperon.
The Mary Pope Osborne series features 54 books. And in those many adventures, the kids end up in the midst of the Civil War, at the first Thanksgiving, and in battle against an evil wizard (they weren't always educational).
If you're worried about Hollywood getting its hands on the beloved books, remember that recent '90s series adaptation Goosebumps went well. Plus, Osborne herself is acting as an executive producer on the film, which will borrow heavily from book number 29, Christmas in Camelot. It should be safe to get excited.