I was losing my mind trying to use the App Hub up here: http://create.msdn.com/en-US/
But, then I found this:
If you're an App Hub member, and are experiencing any of the following issues:
1. Sign out of App Hub
2. Browse to http://www.xbox.com/
3. Click "Sign In", and sign in using the same Windows Live ID as you do to sign into App Hub
5. Return to App Hub (http://create.msdn.com)
6. Sign back in using your Windows Live ID to continue using App Hub as normal.
And now all is happy.