Prisoner of Azkaban

Kevin Wollert has been creating an amazing series of scenes from the Prisoner of Azkaban, including Waiting for the Knight Bus, Buckbeak, and Quidditch. Be sure to follow the link and see them all.

Harry Potter

Adventuresinlego built scenes for teach of the Harry Potter books, including this one from Prisoner of Azkaban.

Inferi

Adventuresinlego built Harry and Dumbledore being attacked by inferi as they were seeking Voldemort's horcrux.

Dementor's Boggart

According to Zaberca, In Dementor school, trainees use boggarts to train against Harry.

Expecto patronum!

Louis K. made Expecto patronum! from Harry Potter and the Prisoner of Azkaban.

Devil's Snare

There just aren't enough Harry Potter builds out there, which is kind of surprising given the official theme and the popularity of the source material. Carson Hart made Devil's Snare from book one. It's so cool that he built his own Fluffy rather than simply buying the official version.