I gave up after a couple hours of staring at this nonsense. I grew so displeased because my app doesn't need 95% of what these libraries offer. I only need to sign requests with a fixed oauthconsumerkey, oauthconsumersecret, oauthtoken, and _oauthtokensecret. However, this simple task would require me to subclass or instantiate several object with Culver's library, and I can't even begin to fathom what I'd need to do with Knapp's offering.
(Aside: if you want to authorize and build access tokens for your app, I highly recommend this excellent OAuth test client)
I finally teased apart the core function of signing requests, thanks in large part to the great reference example. If all you need is to access a protected resource, this will get the job done with a single function call, no object-orientation required.