Although I now teach high school, I spent the last two years teaching at the 8th grade level. I attended training for and taught throughout the school year using the History Alive! curriculum. So, I thought I would see what Wikipedia had to offer regarding their programs. The only entry happened to reference the text that my district purchased to fit the new curriculum map for Social Studies 6-12; The Medieval World and Beyond, so I had experience working with it. I was disconcerted to notice that the entry was extremely biased and, although backed up with links to outside information, contained no balanced information whatsoever.
A quote from the article as I found it:
The book was criticized for having religious propaganda and stating Muslim myths as fact. When a reviewer on Textbook League asked an officer of TCI to tell him what the source or sources of the textbook was, the officer refused to reply. A principal at Houston Elementary said that the book does comply with a California state standard that requires students to learn about diverse religions which is false. The book was removed from the Scottsdale, Arizona school district's curriculum in 2005.
I added some unbiased information about the book. Also, I added links to some sample resources that come as part of the package from TCI (the publisher) and several internal Wikipedia links to other articles such as "Renaissance," "Inca," and "Crusades."
History Alive! The Medieval World and Beyond is a textbook, with companion resources, from Teacher's Curriculum Institute that is intended for middle school age students. It's curriculum covers the fall of the Roman Empire, feudalism and the role of the Roman Catholic Church in medieval Europe, the Byzantine Empire, Islam beliefs and culture, the Crusades, west African culture, Imperial China, medieval Japan, the Maya, Aztecs, and Incas in the Americas, and the European Renaissance and Reformation. Purchase of the textbook includes lesson plans and activities that provide students with activity based learning. 
Click here to see the article.
Since I made the edit and then forgot to check in a week later, I'm glad to see my edits have survived for almost a month!
On another note, the disconcerting part of my editing experience is what stuck with me. The article I edited was, and still is, an "orphan" and a "stub." This means that there aren't very many other articles that link to it and that the article itself is relatively short. Without my edits, a student who decided to do some research on this textbook would only find the biased information. I would hope that student would bring his concerns to a teacher so that an educated conversation could follow. Although each and every opinion on this text should be considered before a school district adopts it, the information on Wikipedia was not balanced. It would not give a student a fair representation of the value of the text when the information is taught by a teacher with an eye for delivering content in the proper balanced fashion. This kind of critical evaluation is something we need to teach our students. When starting research, I often advise my high school honors level students to start with Wikipedia. They can get a decent overall review of their topic and good articles have links to legitimate scholarly resources at the bottom. While Wikipedia cannot be cited, many of these linked resources can be used and cited in an annotated bibliography. My hope is that my students read Wikipedia with a critical eye. Although the biased perspective expressed in the entry I edited is a valid point of view, it is not the only perspective on this particular textbook. Would most students know that? Or would they assume the entry is accurate and take that point of view as the only valid one?