The MonoDevelop front page (http://monodevelop.com) advertises 3.0. The download page advertises 4.0, but its release notes direct you back to the homepage.
When you actually download 4.0, you get something called Xamarin Studio which acts like MonoDevelop with a mobile development flavor.
To top it all off, it auto-updated and the add-ins repository just gives me 404 errors now.