This article describes what Anita McCafferty and Jeffrey Beaudry did when they were were given a two-hour time block for professional development on a Friday afternoon just before the school district went on a week-long vacation. Their audience included 175 K-12 teachers and administrators from a school district in Maine, and their topic was assessment literacy. In order to maintain the adult learners' interest and meet their learning needs, they chose an interactive immersion "gallery walk" to present information about foundational classroom assessment literacy concepts and skills. A gallery walk is a discussion technique that gets learners out of their seats and invites them to become active participants in the learning process. McCafferty and Beaudry added new strategies to engage small and large groups of adult learners and their mobile technology. They describe their approach herein.