We've reached out to the Android community team for a comment, but in the meantime all you and I can do is idly watch the Market fail from the sidelines. We'll update this post when we know more.
Here are some of the failing apps: 1, 2, 3, 4.
Update 6/2 10:30 p.m. PT:
Update: 6/3 12:30 a.m. PT: All back now for me. How about you?
Update: 6/3 1:30 p.m. PT: Google reached out to us and let us know everything was back to normal. No reason was given.