They're being tricky, using javascript to stop most leechers. I don't know much on it, but it seems the video is called in this section:
HTML Code:
AC_FL_RunContent(
"src", "/media/educatorn",
"width", "1150",
"height", "375",
"align", "middle",
"id", "educator",
"quality", "high",
"bgcolor", "#000000",
"name", "educator",
"allowScriptAccess","sameDomain",
"type", "application/x-shockwave-flash",
"pluginspage", "http://www.adobe.com/go/getflashplayer",
"allowFullScreen","true",
"wmode","transparent",
"FlashVars", "course=mathematics/calculus-bc/murray&lecture=Calc2-1-1"
);