With the Sensei plugin you can create courses, write lessons, and add quizzes into WordPress.
http://www.woothemes.com/products/sensei/
Frameworks · WordPress Theme
Get access to data on 21,117 websites that are Sensei Customers. We know of 5,689 live websites using Sensei and an additional 15,428 sites that used Sensei historically and 3,256 websites in the United States.
Get a list of 21,117 websites using Sensei which includes location information, hosting data, contact details, 5,689 currently live websites and an additional 6,552 domains that redirect to sites in this list. 15,428 sites that used this technology previously and 3,256 websites in the United States currently using Sensei.