Wikipedia is usually a dirty word in educational circles. While some educators realize the value of Wikipedia as a starting point for research, others uphold a blanket ban - Wikipedia articles should not be cited - which results in Wikipedia being ignored despite useful references in the more robust articles and the possibility of using it as part of an assignment being discounted.
The latter idea holds many possibilities. A few educators at the University of British Columbia have set Wikipedia assignments for their students. This involves students editing articles in their subject area to improve the quality of the article. The improvements, in several cases, were dramatic:
Remarkably, at the end of the project, Beasley-Murray’s students ended up producing eight “good” articles and three “featured” articles, whose designations recognize them to be the most unbiased, well-written, and accurately cited entries on the site. Before receiving the elusive “featured” title (less than 0.1% of all Wikipedia articles obtain this designation), one of the entries had undergone over 1200 revisions - a number significantly higher than what an average academic article typically receives.
You can read more about the UBC experiences with Wikipedia assignments. Wikipedia also has a page dedicated to school and university projects and a list of suggested projects.