In wp-admin, I clicked to automatically upgrade from WP 3.2.1 to 3.3.
After the upgrade was finished, /wp-admin/about.php?upgraded (or similar, can't remember exact URL) tried to load, but I received the error:
Fatal error: Call to undefined function get_option() in /home/erotic/public_html/wp-admin/admin.php on line 32
I renamed /wp-content/plugins to /wp-content/plugins.bad without change.
I renamed /wp-content/themes/currenttheme to /wp-content/themes/currenttheme.bad without change.
I downloaded WP 3.3, unzipped, and uploaded /wp-admin over the top, without change.
Same thing with uploading /wp-includes, still the same error.