Classify Two Dimensional Figures  (You will need to scroll down to the last choice named "Classify Two Dimensional Figures".  You will be able to do several questions before asked to register for the site.  You do not need to register.)

What are Polygons?

Classifying Quadrilaterals : Shape Inspector (You need to read the instructions and then scroll down to play the game.)

Classify Angles

Classifying Triangles

Polygon or Not?

Polygon Game