Free CLEP American Studies Tests.
http://www.testprepreview.com/american-government-questions.htm
Selection of 10 questions on CLEP American Government. This free CLEP test comes complete with answer key.
http://www.speedyprep.com/clep-practice-test/free-clep-american-government
The 15 questions on this practice test are similar to those on the CLEP American Government test. The answers come with useful feedback. Best of all the questions are updated each day so you can test yourself on a regular basis. A great way to reinforce learning.
http://www.cleptestquestions.com/american-government-questions.html
The free CLEP American Government test provides 10 practice questions with answers.
http://www.cleptestreview.com/american-government-clep
On this site CLEP American Government is broken down in to several subject areas and each subject has its own quiz (monthly cost). At the end there is a timed one hour exam (free) that will be a useful test of your readiness for the real thing.