These sorts of things are often tricky for citizens. The Boston Globe has a sample of the test given to immigrants who want to become citizens.
MSNBC has a more interactive version here. And there are 100 questions from the U.S. Citizenship and Immigration Service here. However, new questions will be on the test this October.
Tomorrow afternoon, by the way, the Mall of America is hosting a naturalization ceremony.
Tangent time: Today a veteran of two tours of duty in Iraq was sworn in as a U.S. citizen. And in Canada, yesterday, the son of a World War II soldier and a war bride, who had his citizenship stripped from him by the 1947 Citizenship Act, and who labeled a bastard in the process, got his citizenship back.