What book or movie had the most annoying cliffhanger ending?

It never fails: You're 30 pages from the end of a book, or 15 minutes from the end of a movie, and you start to wonder, "How are they going to wrap all this up in the time remaining?" And then... they don't. Which book or movie ends on the most frustrating cliffhanger?

Please include a picture, book cover, or clip of the book or movie in question. And please let us know the title, and why it was so frustrating. Thanks!

Top image: The Matrix sequels.