The citizenship test they use for naturalization looks easier than the Presidents' Day test or the Fourth of July test. Of course, this would be a lot harder if the test taker had a limited grasp of English.

These are the questions and the answers to what I asume is the most recent set of 100 questions. You have to answer 6 out of 10 that they pick out. It is an oral test too.
http://www.uscis.gov/files/nativedocuments/100q.pdf