Area and Perimeter Games

http://www.mathplayground.com/PartyDesigner/PartyDesigner.html
http://www.mathplayground.com/area_perimeter.html
http://www.funbrain.com/poly/
http://resources.woodlands-junior.kent.sch.uk/maths/measures/measure.html
http://mrnussbaum.com/zoo-play/
http://pbskids.org/cyberchase/media/games/perimeterarea/

Google "area and perimeter games" for many more!