In this new post to his blog Cal Evans talks about a project he was working on that needed to interface with Twitter via their API. This, of course, requires OAuth but his script is all backend and Twitter requires a frontend to allow the application access.
There is no front end at all. It just collects info and stores it in a database so I can query it later. (I'm an old-school database guy and love just writing ad-hoc queries to see what I can see) Twitter wants to redirect you to a site once you have authorized access. Since I don't actually have a site to redirect it to, this was a problem.
His solution ("in two parts") involves tips from two different blog posts - this tutorial from Michelangelo van Dam and the other from Jaisen Mathai about using OAuth with Twitter. He's not releasing the source for his script just yet, though, so you'll have to do a little research on your own.