Granted, these numbers from Pew Research are based on a 2010 survey, and the Supreme Court has been getting a bit more visibility of late, what with the debate over health care and all. But still! Thurgood Marshall? The guy has been dead since 1993 and he was never Chief Justice. Harry Reid is Senate Majority Leader, and John Paul Stevens - never a Chief Justice either - retired by the time this poll was taken. The Washington Post's Chris Cilliza calls it "the most amazing Supreme Court chart - maybe ever."
Regular people are simply not engaged -- they don't know or care -- about the intricacies of the government in a way that people who live inside the Beltway and spend their lives in politics are. It's a lesson we have to re-learn constantly.