Homebrew Computer Club
From Innovation
Starting in 1975 a number of computer-building hobbyists met around Menlo Park and Palo Alto, California. This can be said to be a case of user innovation.
The history's discussed in many places:
Episodes of Collective invention paper: http://www.bls.gov/osmr/pdf/ec030050.pdf
Steven Levy, Hackers
Freiberger and Swaine book Fire in the Valley
Elizabeth Petrick is doing more research in this area. (SHOT 2008 meetings)