Skinning the cat in a different way, you might start with a perspective as Curt suggests, then use UI scripting to select all the items, copy them to the clipboard, and paste them at the end of your text file in TextEdit or BBEdit or TextWrangler or the like. This approach would only get the task names, however. A web page with a reasonable example of this technique can be found at
http://www.elegantchaos.com/node/159
I would agree that using the Applescript primitives supplied by OmniFocus is a more robust solution, but the UI scripting bit is a useful thing to know when you're needing to script something where the developer hasn't given you the tools.