Slooh.com is an website designed to help you learn about space. Although it isn’t free, the $300 classroom license with 30 students is reasonable. Once you become a member of Slooh.com, you can take part in several cool activities:
- Control of 6 telescopes, allowing you up to 20 hours of sky viewing. You can make reservations to few particular objects too.
- Access to astronomers. Ask questions of real life astonomers.
- Quests. Gamified learning of space.
All in all, I would have loved to have had access to something like this in high school!