We propose a theoretical framework to understand the effect on a movie's eventual theatrical success of leading the box office during the opening weekend. We consider two possible channels: a positive shock to the utility from watching the movie and a greater awareness of the movie's existence. We derive a series of testable predictions, which we test on U.S. box office data. The results suggest that being #1 in sales during the opening weekend has an economically and statistically significant effect on the movie's total demand; and that the primary channel for this effect is through the greater awareness induced by being #1.