Curiosity.com is a website from the Discovery Channel. It is visually appealing, and has many topics that you might be, well, curious about. For example, you can see the 30 strangest landmarks in America or view an image gallery of geniuses.
Curiosity.com is not “vetted” for educational purposes, but there is a link to Curiosity in the Classroom, which is. Curiosity in the Classroom offers resources for parents, students, and teachers including lesson plans and downloadable activities. It also gives information on careers and fun quizzes for students to take. This portion of the site is aimed at students in 6th-12th grades.
If you have secondary students who are working on independent projects, but cannot seem to narrow down a topic, Curiosity.com might be the place to send them.