This document discusses designing science lessons for deep, intrinsic student engagement and fun. It begins by exploring the meaning of fun in science education and approaches for achieving deep fun. Examples of tools for lessons include storytelling, hands-on experiments, and role-playing. The document also discusses a mastery learning 5A framework and 10 engagement tools based on Roger Bybee's 7Es model. Case studies show how the approaches have improved student understanding and engagement in lessons compared to traditional "chalk and talk" methods. The document concludes with brainstorming what deep fun means for teaching science and a workshop bringing together educators to discuss these topics.