On this website, you use graphics to create a story. The options are a little limited, but it could help in generating ideas for creative writing. Although this website may seem a little juvenile at first glance, it is actually very fun and I think high schoolers may enjoy it.
This page contains very clearly written advice and steps on how to revise a paper. I think it would definitely come in handy for both inexperienced and experienced writers.
This website contains valuable and interesting information on all types of mythologies from cultures around the world. It could be of use in English or history classes.
While this entire website is full of useful information about Edgar Allan Poe (and therefore may be useful in an English class), this particular page is highly interesting. It contains information on all of the major theories on how and why Poe died, which could make for a very fun inquiry lesson.
This website contains explanations and examples of "proper" formatting for specific styles, such as MLA. It is a wonderful resource for writing research papers and the like.
No Fear Shakespeare places the original text written by Shakespeare next to a "translation" into modern English. This is a useful tool because sometimes Middle English can be very intimidating to read, and even if a reader basically understands the meaning, they might not understand all nuances. No Fear Shakespeare helps us to understand what Shakespeare really meant.