We will be using 1 tag and 1 function to accomplish this.

<!--- Set the URL of the page's source you want to view --->
<cfhttp method="get" url="http://www.google.com"></cfhttp>

<!--- Then we display the view source code by doing this: --->
#htmleditformat(cfhttp.filecontent)#

That's all there is! That will display the source code of any URL on the web, this is how it all looks together:

<cfoutput>
    <cfhttp method="get" url="http://www.google.com"></cfhttp>
    #htmleditformat(cfhttp.filecontent)#
</cfoutput>

Have Fun!