Dream within a dream within a dream
Inception (2010, USA/UK, Christopher Nolan)
Alejandro Amenábar beautifully explored the complex world of dreams and reality in Open Your Eyes, later remade into Vanilla Sky. However, the story of both films only explored one level of a dream world. Christopher Nolan has taken that core concept of dreams vs reality and gone two/three levels deeper, thereby creating a hyperlink dream maze that requires multiple hops to exit. Even though Inception traverses multiple dream levels and is bursting with fascinating ideas, it is a remarkably accessible film that manages to explains its ideas in a fluid manner without halting the plot progression. Ofcourse, since it is also a summer film, it contains the mandatory action sequences and explosions, without which the film might not have gotten booked in a multiplex in the first place. Thankfully, a majority of the explosive scenes shot in the Canadian snow-capped mountains arrive in the finale and don't derail the film too much.
note: The story presented in Inception would certainly have made Jorge Luis Borges smile, given that Borges was a master of labyrinths and dreams within dreams.