Not actually a debate, but this week The Guardian is running a series of articles on how to argue properly. I know habituees of GD will be most interested.
I didn’t see any indication that the Guardian will insist its editorial writers must take lessons in the subject, so I think I’ll take a pass.
That gem alone is worth the read.
Edit: and unfortunately sums up much of what passes for “discussion” on the Internet. 
<mod hat on>
More MPSIMMy that Great Debatey, really.
<mad hat off>