HTML to generate clickthrough for download

I’m trying to solve a problem for several hundred independent coders who depend on banner ad clickthroughs to fund their Web hosting. What I want to do is create a link to the downloadable file (e.g., downloadme.zip) that actually clicks the banner ad and only then sends the file to the browser. Presumably, .htaccess would be somehow involved to prevent deep linking.

Is this possible, and if so, what would the generic HTML (or PHP) look like?