SAXON GENITIVE- Explanation and game
http://www.engames.eu/possessive-case-explanation/
http://www.engames.eu/possessive%20case/possessive_case_quiz%20%28Web%29/index.html
POSSESIVES - Explanation and game
http://www.myenglishpages.com/site_php_files/grammar-lesson-possessive-pronouns.php#.VGojuX_1bXR
http://learnenglishkids.britishcouncil.org/en/grammar-games/possessives
And... Try this game. the options are under A, B or C