Move posts in a category and/or a page hierarchy to a new subsite, with seamless redirects.
Many older WP sites used categories and/or pages to organize what were essentially subsites without proper access control and other site-specific goodies like themes, widgets, and plugins.
This plugin lets you move that content to another site on your WordPress network with a single click, with seamless redirects.
This is beta software. Back stuff up first. (I shouldn't have to tell you that, right?)