I visited these wallwishers, Sebastian's wallwisher have a good game and the way to show the comparatives were very  dynamic and I think that could be very usefull to show in a class.

http://wallwisher.com/wall/danimedina  Daniela

http://wallwisher.com/wall/ictcomparatives Sebastian

http://wallwisher.com/wall/educationictsergio Sergio

http://wallwisher.com/wall/ictineducation Begoña