http://www.purplemath.com/modules/slope.htm
http://mathforum.org/cgraph/cslope/
http://www.flashrolls.com/sports-games/Snowboard-Slope-Flash-Game.htm
http://hotmath.com/hotmath_help/games/kp/Karappan_Poochi_Sound.swf
http://www.gradeamathhelp.com/y-intercept.html
http://aix1.uottawa.ca/~jkhoury/game.html
