Curiosity is a new site from Discovery Education that I really like. There is a show that goes along with it, but I haven't had a chance to view it yet.
The site has a huge amount of information and resources on a large variety of topics. You can search by topic or keyword for information. You can also submit a question about something you are curious about and then the answer, with links and other resources, will be posted (or something pretty darn close). They will email you when your question is answered. Many of the answers are from Discovery Education resources, but many are not. It's a great site for teachers to use to find out things, or let your students use it to discover new things and ask questions. Let them ask what every they are interested in and then have them do a project on it.