Wikipedia: Dominoes
http://en.wikipedia.org/wiki/Dominoes

Domino Math Printable: Activities and Worksheets
(Can create templates from this site)
http://www.first-school.ws/theme/printables/dominoes-math.htm

eHOW: How to Play Dominoes
http://www.ehow.com/how_9241_play-dominoes.html

Illuminations: Do It with Dominoes
http://illuminations.nctm.org/LessonDetail.aspx?ID=U47

The Mathematics of Dominoes
http://www.pagat.com/tile/wdom/math.html

Math Games: Domino Graphs
http://www.maa.org/editorial/mathgames/mathgames_12_15_03.html