If you’re a student and you don’t know what this site is, I’m not really sure where you’ve been, because this site is extremely useful for studying.
I’ve been using khanacademy.org since I was younger, when the overall interface was kind of weird, and everything was still focused on math. No worries, now Salman Khan’s Khanacademy is a lot better than it was earlier, with tons of videos teaching you practically anything textbooks have to offer.
There are also fun little challenges and the ability to ‘master’ certain skills and earn badges to flaunt to your friends. You can also earn energy points, which unlock avatars for you to use.
Aside from that, the beautiful thing about this site is that it truly believes that primal memorization makes you a shadow of your true potential. It aims to help you understand what school is forcing down your throats, all without charge. Say no more, I have provided the link. Just click on the picture.
I should actually be studying now…