Part of the Volume on the Ecology of Games: Connecting Youth, Games, and Learning. This essay describes the design and successful deployment of a series of massively collaborative game missions in I Love Bees, the alternate reality game. Alternate reality games (ARGs) are massively multiplayer puzzle adventures that combine online interactive content with real-world game events. McGonigal proposes "stimulating ambiguity" as the central design philosophy of ARGs. She explores how ambiguous game content stimulates massively collaborative game play that allows for a greater share of leadership and meaningful participation in large-scale player groups. She also outlines how the open-ended puzzles of ARGs inspire multiple, creative interpretations that allow for diverse problem-solving strategies to flourish in a single player community. The essay is grounded in a close reading of player-produced content and their interpretations of the core puzzle of the I Love Bees game: a series of several hundred GPS coordinates, dates, and times that were listed on the central game Web site.