While GTK+ 2.24 is now final, version 3.0 is still being worked on but is almost done. GTK+ 2.99.3 is the new release and it also comes with one last ABI break before going gold. GTK+ 3.0 is expected to be declared stable next week.
This near-final release brings many introspection annotation improvements, visual improvements to the file chooser and application chooser widgets, restored support for key themes, and many other last-minute technical changes. There's also now a migration guide and tutorial for GTK+ 3.0 within the documentation pool.
The GTK+ 2.99.3 release announcement can be found on the gnome-announce-list.
GNOME Shell 2.91.6 provides the standard desktop interface for the GNOME 3.0 desktop and new in its 2.91.6 release is a new calendar design with integration to the Evolution Data Server for supporting calendar appointments, new shell-themed dialogs for log-out and shut-down, Google and Wikipedia search buttons, a keyboard layout selector is available from the system status panel, a change in the default GNOME Shell font (to Cantarell), improved shadow support, accessibility support, user-interface tweaks, visual tweaks, and much more. See more in the release announcement.
The Clutter-based Mutter is also up to version 2.91.6, but there isn't anything overly exciting in the new release.
GNOME 3.0 will go into beta early next month and will be officially released in early April. Look for the GNOME 2.91.6 release tomorrow.