Inception

When the director of some of the best movies of recent years (The Prestige, Memento, The Dark Knight), makes a movie about dreams (a field of study that the modern science has very little knowledge of) starring Leonardo DiCaprio, one of the best actors to have come up in the past decade, the expectations are incredibly high. Inception,  unsurprisingly surpasses all the expectations that hardcore Nolan fans may have had. It is grand, it is intelligent, and most importantly, it is awesome.
Sample the premise: it is a world where it is possible to invade dreams and steal ideas. The protagonist, Dom Cobb (played by DiCaprio), is the best thief in the business of dream invasion and deception. He has had a troubled past due to separation from his children. He is given a last impossible chance at redemption: inception, meaning he needs to plant an idea instead of stealing one.
With a premise that is as innovative as this, you already have the audience engrossed. All you need to do thereafter is to lead the movie to an impressive conclusion. Nolan does not only manage to do this but he also manages to make the journey to the climax unbelievably enthralling to say the least.
Inception has only one problem: it is very complex. It took Nolan ten years to outline all the nuances of subconscious invasion and inception. So, it is only understandable that it can be really difficult for the audience to catch all these nuances in a 148 minutes watch. His movie requires multiple watches, but since it is exceedingly engaging, you are unlikely to get bored. All the clues to understanding the movie are there in it; your job is to watch it alertly and solve the puzzle.