Planet Ebook offers over 80+ free classic books for free on your computer or mobile device. This would be a great resource for middle or high school students who have a reading goal that includes classic literature.

In researching Khan Academy more in-depth, I've found that there is a section called Hour of Code under the digital resources. I use "Hour of Code" from code.org, but this resource actually takes you through 10-15 steps of the coding process, with short videos to open each section, and then they have the kids complete the task. You can sign up for a free 30 day trial if you don't have a login for Khan. Then you can create a class list, assign students, etc...The content would be ok for 5th grade and up.