Indiana Jones and the Kingdom of the Crystal Skull
4
I saw this movie and thought it was a good film. It was true to the spirit of the previous Indiana Jones movies. I'd rank it as being quite a bit better than the third in the series, the "Last Crusade" movie, which I felt was disappointing.
In this one, the special effects were good and there was plenty of action and humor. Indiana Jones movies are essentially remakes in the style of old crowd-pleasing cliffhangers and are not meant as serious adventure dramas. As long as you understand that going in, you'll probably enjoy this film too.