Polygon Matching Game
Quadrilateral Quest
Polygon Game
Polygon Playground
Tessellations - Tessellations.org
Shodor Interactive - Tessellations
Tessellation Town
Tangrams from NLVM (National Library of Virtual Manipulatives)
Tangram Game from Cyberchase
Shapes that Tessallate
TesselationTutorial - http://mathforum.org/sum95/suzanne/tess.intro.html
Other Tesselation Links - http://mathforum.org/sum95/suzanne/links.html