I don't want to say too much about Jean-Pierre & Luc Dardenne's Le Fils (The Son), because I wouldn't want to spoil any of it for those who haven't seen it, but I will say that this film is brilliant. It centers around a man (Olivier Gourmet) who teaches carpentry at a center for—what we call in this country—"at risk youth." A teenage boy comes to the center and wishes to be taken on as an apprentice to the carpenter, and though the carpenter refuses (he has too many pupils as it is) he immediately becomes obsessed with the boy and begins to follow him. The Son is a fascinating character study about a complex, confusing man and I found the movie to be absolutely riveting from start to finish. The Dardenne brothers wind the tension up exquisitely and when it breaks (as it must) the audience has no idea what will happen next.
I saw this film in preparation for the Dardenne Brothers' L'Enfant (The Child), which is playing at a theatre near my house, and if L'Enfant is anything like Le Fils, I know I'm going to love it.