What are the ways of monetization educational web-project?
Actually I consider just Google AdSense because it's not very disattractive for users. Can anybody tell me how much users per day do I need to earn $500 per month with AdSense (it would be enough to maintain and develop the project)?
Suggest any other ways of monetization such or related kind of sites.
About project: it's educational site about java (actually), with articles, video and audio lessons, verification of completed tasks and questions-flow (like StackOverflow, but questions about java or about client-side programming and it's very simple now).
Thank you for all answers.