How do I dynamically create an html page that I can assign to the body of an email?

Hi,
 
I would like to send an Html email. The body for this email I would like to create completely dynamically. How do I create an html page completely from scratch so that I then have a page that I can add controls to? Do I create an instance of the System.Web.UI.Page class, add my controls to it and then render it as a string that I can assign to the message body?
 
thanks,
Duncan
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