Professor Nancy Van House has posted her evolving syllabus for IS212, Information in Society. Lots of good stuff, many with direct links to the papers themselves.
From my experience auditing the course last semester, my favorites are:
Engeström,Yrjo. Expansive Visibilization of Work: An Activity-Theoretical Perspective. Computer Supported Cooperative Work 8: 63–93, 1999.
Nardi, B. (1996). Activity theory and human-computer interaction(pp. 7-16); and Kuutti, K. (1996).Activity theory as a potential framework for human-computer interaction (pp. 17-44). Both In B.Nardi (Ed.)
J. Johnson [Bruno Latour] (1995): “Mixing Humans and Nonhumans Together: The Sociology of a Door-Closer” in Susan Leigh Star (ed.): Ecologies of Knowledge: Work and Politics in Science and Technology. pp. 257-277.
Hutchins, E & Klausen, T. (1996)Distributed cognition in an airline cockpit. In Y. Engeström and D. Middleton (Eds.) Cognition and communication at work. New York: Cambridge University Press.
Bijker, W. E. (1995). King of the road: the social construction of the safety bicycle. In Of bicycles, bakelites, and bulbs: Toward a theory of sociotechnical change (pp. 19-100). Cambridge, MA: MIT Press.
These two were probably the most mind-changing:
Latour, B. (1999). Pandora’s hope : Essays on the reality of science studies. Cambridge: Harvard University Press. Chapter 2: Circulation Reference: Sampling the Soil in the Amazon Forest.
Latour (1986) Bruno Latour, ‘Visualization and Cognition: Thinking with Eyes and Hands’, Knowledge and Society 6: 1-40.
(This one will be very hard to find, but damn is it good.)