It's directed by Brad Bird, who also directed The Incredibles and Ratatouille (one of which I loved, one of which I didn't - but that's another post for another day), and it tells the story of a young boy named Hogarth who discovers a giant robot from outer space while living in a small town in Maine in the late 50s.
The cast includes Jennifer Aniston, Harry Connick, Jr, John Mahoney, Christopher McDonald and Vin Diesel as the Giant. Jackson's favorite sequence is where Hogarth crushes a laxative on top of a sundae about to be eaten by McDonald's character - shocking, a 6 year old boy laughing at doody jokes. I prefer the Giant's love of Superman. Regardless, there's something for everyone here (and plenty of something if you like old Sci-Fi and comic books).
A word of caution: some scenes might be too intense for little ones (Griffin, for example, is fascinated and frightened by the film).