Wikibooks
- developing free, open content textbooks, manuals and other texts. Currently have over 120 textbooks in various stages of development.

Wikisource is a repository of source texts in any language which are either in the public domain, or are released under the GFDL. Something like project gutenberg. They don’t have as much as gutenberg, … yet.

disinfopedia - describes itself as a collaborative project to produce a directory of public relations firms, think tanks, industry-funded organizations and industry-friendly experts that work to influence public opinion and public policy on behalf of corporations, governments and special interests.

dkosopedia - a collaborative project of the DailyKos community to build a political encyclopedia.

PESWiki.com - specializing in ‘free energy’ technology, using wikimedia to build encyclopedia, news, open sourcing technology, events, PAC, academy, library and more.

unilang.org - languages, linguistics, and language acquisition

wikitravel.org - a project to create a free, complete, up-to-date and reliable world-wide travel guide.