What is it:  iPlaymathgames.com has just gone free after offering a subscription based service for some time now.It offers a range of K-12 Maths games and activities in PDF format for you to download.  You can search and filter for specific areas such as division, fractions, measurement, etc.  All games have been developed and tested in classrooms with real students and educational professionals. In many cases, there is no "winner" in the games and activities being played. Rather than create outright competition, most games and activities will foster only math skill building. However, with the world and students as they are today, there are myriad games on the site that do allow differentiated instruction for an interested math learner who wishes to test their budding skills against their peers.

How can I use this in the classroom:  Pick out the subject area you are focussing on for the week and you will be sure to find a specific game to suti the age and needs of your students.  In either whole class or small group work shops.  Check it out here.