Homo economicus, the legendary self-interested creature of the economics classroom, prefers free riding to to contributing to public goods, doesn't vote (Marginal Costs being greater than Marginal Benefits) and would surely not be interested in wasting time listening to Ralph Nader's call to civic engagement, given in a talk in Montreal in 2006. Fortunately, not many people behave like that (although, it seems, some economics students may be persuaded to do so...).
It's available here in video (which can also be downloaded). Great listening if you need inspiration to get involved in something again: http://www.cerium.ca/Ralph-Nader-un-appel-a-l
PS. There is a link to Nader's blog on this page.