Across Canada there is increased attention to the important relationship between the quality of learning environments--particularly effective teaching--and student achievement. "What did you do in school today?" proposes a multi-dimensional framework of student engagement as a core idea for improving the quality of teaching and learning in ways that will most directly benefit adolescent learners and advance the social benefits of learning. In addition to the established concepts of social and academic engagement, the research contributes to the newer concept of intellectual engagement. The research framework considers student engagement as a learning process and outcome that is directly or indirectly affected by what happens at home (i.e. family background) and the school/classroom-learning climate (i.e. learning time, relationships, instructional challenge). Results from 32,322 Grade 5 to 12 students in 93 schools from 10 districts across Canada are presented in the report, which uses a variety of methods (descriptive, correlations, odds-rations) to answer four research questions: Are Canadian youth engaged at school; How much does family background matter; do schools make a difference; and, does instructional challenge make a difference? Results indicate that: levels of intellectual engagement are considerably lower than social and academic engagement; relationships among the three dimensions of engagement are weak at the student level and stronger at the school level; levels of engagement are related to students' socio-economic structure and family structure, but much stronger effects are noted from the school and classroom-learning climates in schools; and less than one-half of Canadian middle and secondary school students experience flow (Csikszentmihalyi, 1991) in learning mathematics and language arts. The report draws attention to the importance of exploring what these findings mean for Canadian schools and school districts in the context of a framework that offers five effective classroom practices for creating more socially, academically and intellectually engaging learning environments. Findings also point to local, regional, and provincial consideration of strategies to raise overall levels of student engagement, practices that will help to boost students' experience of social, academic and intellectual engagement in middle and secondary schools; and addressing the two separate but parallel issues of students who feel that their work is too challenging and those who feel that the challenges of learning are too few. (Contains 32 figures and 2 footnotes.)