1. Inception (2010)
Director: Christopher Nolan
Starring: Leonardo DiCaprio
A thief who steals corporate secrets through the use of dream-sharing technology is given the inverse task of planting an idea into the mind of a CEO.
In the film the topic of collective lucid dreaming and dream levels is well showed, which is definitely interesting.
2. Waking Life (2001)
Director: Richard Linklater
Starring: Trevor Jack Brooks
A man goes through different layers of a dream, meets characters in them, discusses the meaning of the Universe with them, and gradually gains more and more awareness. If at the beginning of the plot the main character is in an ordinary dream, then step by step his awareness arises.