Although, I sort of put my CWNA studies on the back burner because I am focusing fulling on the CISSP studies, I still trying to do some simple reviews on CWNA once a day.
The CWNP.com offers a really good Questions of the Day multiple choice quiz every day. It is a new question every day to test your wireless knowledge. Check out the link below.
Since the questions changes everyday, when I finish answering the question and get the correct answer, I use the clip to evernote extension in Chrome to keep a copy for future reference. It is a great way to build up a free question library and a good way to keep your wireless knowledge fresh.