The early reviews on Toy Story 3 make it look like Pixar has done it again. I intend to verify that for myself later on this weekend, and I'll be curious to see how the film ranks not only among Pixar's impressive achievements but in that category of films that are third in a series. The third episode is where even the mightiest moviemakers can reach beyond their grasp, The Godfather Part 3 being the saddest example of the risks involved. But sometimes it's only on the third time around that a series really hits its stride, even if it ends there, too. The third episode of a trilogy, after all, probably ought to be the best, but sometimes it's the third film that assures a series of many more installments, or at least gives it a promise of fresh life.
The following is a tentative list of my favorite "threequels," taken from an inevitably incomplete sample. I'm sure that older viewers could cite third episodes from some of the great B-movie series of the 1930s and 1940s, for instance, though you will see one film from that period here. For my purposes, a series is a set of films that form a conscious narrative sequence or follow a consistent character through continuing if often unlinked adventures. One film on my list is arguably an exception to this rule that might bring other exceptions to mind. For the historical record, this list is as of June 17, 2010. Later, after I see Toy Story 3, I'll let you know whether it earned a place on the list.