Here are some of my favorites:
* Daily Grammar Archive: This is a whole grammar curriculum, well laid out, easily accessible, and free.
* Glencoe Literature Library: Fantastic free study guides on dozens of novels, from Across Five Aprils to The Yearling, on both middle reader and high school levels.
* Purdue's Online Writing Lab (OWL): Another fantastic grammar and writing resource, with printable quizzes and handouts.
* Lapbooking at Squidoo: This has been by far the most helpful site for me in learning the art of lapbooks. I can always go here for ideas and a lot of free downloads.
* CurrClick: I love the free download every Monday. I have a big file of future lapbooks and notebooking pages I've downloaded. Someday maybe I'll get to them…
* Enchanted Learning: I can't possibly say how many times I've used this site over the past 9 years. I did pay the $20/annual fee for a couple of years, but I haven't for awhile. It seems like we are using my favorite site less and less as the kids get older.
* Scott Foresman Grammar and Writing Handbooks: I couldn't resist one more grammar resource. You can download entire workbooks for K-6th grade. Fabulous!
(See more educational freebie sites here at Heart of the Matter Online.)