I didn't watch the movie The Titanic for ten years because I already knew how it ended: the boat sank. Which is what makes the idea for a sequel that much sillier. Despite the 1980 movie Raise the Titanic and the 2010 film Titanic II (which is about another boat named Titanic II), people tried their hand at making a sequel to the 1997 disaster romance epic. Some are pretty good, considering what they had to work with.
Titanic: The Sequel
An excellent idea (for a trailer mashup).
Titanic 3: Never Let Go
Lego Titanic 2
Not really a sequel, but the main story with Lego minifigs.
Titanic II If Jack Had Lived
Using footage from Revolutionary Road.
Titanic: The Animated Musical