Oh, codemonkey. I know you'll be back to do some iHub programming soon. So, one more idea to throw out there.
RB has a great concept with marking the OT posts as OT. But it doesn't do much else.
What would be great (and something to add to the premium feature set) would be to allow for filtering of posts marked as OT. Then, when you post, just have a radio button to check (default: OnTopic) to make your post offtopic.
Really, there shouldn't be too much offtopic, but it does happen. Even under Matt's censorship. :)