Jack Black is the whole show here and that's OK

Rating: 7/10 (12 March 2015)

Jack Black had one of the best roles of his somewhat questionable career in 2003's School of Rock an entertaining comedy that provides pretty consistent laughs in addition to a moment of genuine warmth here and there.
Black plays Dewey Finn, a homeless and penniless wanna be rock star who is crashing at his best friend's apartment, who one day takes a phone call, meant for his friend, accepting a position as a substitute teacher at a local grade school. Bored with teaching history, Dewey takes it upon himself to form a rock band out of the students in the classroom, on the DL, without the school's principal (Joan Cusack) finding out.
Black found a role that fits him like a glove here. He is completely and naturally hilarious as Finn not only teaches the kids rock music but tries to educate them about the history of rock music as well. It's fun as we get to watch Finn bring some students out of their shell musically and put other students' egos in check as well as getting the tightly wound principal to lighten up as well.
Richard Linklater's energetic direction, along with the performances of Black and Cusack that are the primary selling points here, not to mention Black's effortless charisma with the children that makes this film definitely worth checking out.