Too many students in Freshman Calculus are unprepared for the pace at which new concepts are introduced, are unable to implement prerequisite Algebra skills, and are unwilling to seek answers to their questions in front of their classmates. We report on how the Department of Mathematical Sciences at Clemson University, through a partnership with the Computer Science Department, has used Tablet PCs and the web-based interactive software, MessageGrid, to address these issues over the past four semesters. Pen-technology in large-enrollment contentheavy Calculus courses provides new ways to communicate with struggling students: projection of anonymous student-inked submissions; "personalized" feedback on group activities; studentgenerated audio-video podcasts; in Fall 2008, quick identification and remediation of weak algebra skills via inking on Mathpad, and in Spring 2009 through an NSF grant, tagging of student errors in inked responses. We report a higher percentage of students able to enroll in second-semester Calculus. Despite this emerging evidence of greater student success and despite very positive faculty and student perceptions, it is not easy to expand the set of math faculty willing to try the technology. Yet, interest in Tablet PCs (and MessageGrid) is flourishing at Clemson, due to a 2007 Hewlett Packard Leadership Grant which placed Tablet PCs into a multidisciplinary technology classroom and attracted faculty from Engineering and other departments willing to invest time to learn new pedagogical techniques.