Audience agency, text-reading practices, and the roles mediated cultural texts play in the lives of readers have long been at the center of enduring debates among Critical, Cultural, Performance, and Rhetorical Studies scholars. One salient ongoing dialogue among scholars and critics questions the degree to which audiences actively participate in the process of making sense of mediated texts. How capable are media consumers of comprehending and responding to texts containing oppressive discourses? If pop culture is vital in shaping what it means to belong to a culture, can politically minded consumption of cultural texts be a tool by which we can resist or subvert dominant ideologies? This study enters into this dialogue through critical engagement with the emergent embodied audiencing practice of movie riffing, which is characterized by performers talking back to a film, or any matter of mediated text, as it is screened, through a series of humorous and/or critical speech acts. Embracing performative riffing as both a text-reading ethic for negotiating ideologically loaded pop culture texts and a space-based return of embodied performance in a social setting typically characterized by stillness and silence, this study explores the present state of riffing and looks to riffing's future by theorizing a movie-riffing ethic that constitutes explicitly political performance. This study is divided into eight chapters. Chapters 1 and 2 consider contemporary and historical anecdotes on audiencing practices to situate riffing within a rich legacy of embodied audiencing, text appropriation, meta-commentary, and ritual performance. Chapter 3 discusses the theoretical implications of riffing by situating riffing in scholarly discussions concerning audience agency in making sense of ideologically loaded pop culture texts; I argue riffing explicates the possibilities and constraints of audience agency, all of which should be recognized if riffing is to become a valuable performance tactic by which consumers of U.S. popular culture might enter into struggle over ideologically loaded cultural texts and reclaim a space for embodied audiencing in the cultural marketplace. Chapters 4 through 6 are dedicated to site- and text-specific inquiries into the current state of performative riffing and embodied audiencing. Chapter 4 chronicles my initial foray into ritual embodied audiencing with an ethnographic account of the 24-hour participatory "bad" movie festival B-Fest. Recounting my experiences of a B-Fest spent riffing alongside a group of enthusiastic B-Fest aficionados, I consider both the shortcomings and potential power of B-Fest riffing as a participatory, embodied audiencing ethic. Chapter 5 continues my exploration into site-specific audiencing rituals and weaves elements of text-specific inquiry, as I examine the popular audiencing ritual of the 2003 film The Room through a lens of Victor Turner's social drama model. I argue The Room's audiencing ritual and its related performances constitute part of a discursive struggle between the film's fanbase and the film's director, Tommy Wiseau, to claim the film's enduring success as a midnight movie phenomenon. In describing ways in which audience members interact with the film and each other during screenings of the film, I explore the implications of tactical in-theater performance in reading pop culture texts. Chapter 6 moves out of the realm of physical theaters and into the world of popular media as I explore today's most famous and influential riffing showcase, Mystery Science Theater 3000, and consider the tactical strengths and weaknesses of its model of movie riffing as a vessel for cultural criticism. I undertake a close textual reading of MST3K's characteristic movie riffing and identify themes that politically minded riffers might utilize to aid their efforts to read and potentially challenge ideologically loaded texts. Yet, recognizing that the discourse of the show at times showcases problematic attitudes that can be read as destructive or offensive in ways that suggest ridiculing a text is not necessarily the same as subverting it, I also consider ways in which MST3K's model of riffing falls short or presents challenges--and, therefore, avenues for innovation and growth--to politically minded riffers. Chapters 7 and 8 reflect on the lessons gleaned in previous chapters to articulate theoretical contributions and future directions for riffing and embodied audiencing practices. Chapter 7 reflects upon the observations and ideas gathered in Chapters 4 through 6 and localizes them in three related contexts--amateur riffing and online communities, mediated activist art, and the political use of humor--which I offer as further illuminating possibilities, challenges, and new directions and paradigms for riffing. Finally, Chapter 8 draws from my observations in Chapters 4 through 7 and discusses future directions that performative riffing and embodied audiencing performances provide as text-based discursive tools for interpreting and critiquing mediated cultural texts and the ideologies and interpretations of reality they convey. I glimpse into the future of riffing and in-theater performance and discuss the possibilities of riffing as a method of political performance by which media consumers can talk back to mediated texts and those texts' ideologies and interpretations of reality.