CurrClick offers free downloads as well as great resources you can purchase.  This week they are offering

Math Mammoth Clock - a great lesson which teaches as well as reviews the clock.  I often find with my children that even though we've always taught the clock, there is a tendency to 'forget' how to read one...this will make great summertime work...quick and easy lessons they can do in just a few minutes to keep their minds fresh through the summer playtime!