As a parent/educator with an interest in language arts, my favorite, website is Carolyn's Corner. You wouldn't know by the name, but Carolyn's Corner is the official Scripps Howard National Spelling Bee page. Carolyn is an English major>Teacher>Mom (mother of a National Spelling Bee champ) who is creating fun and challenging weekly games and puzzles on the internet for kids. She uses popular literature (The Phantom Tollbooth, The Secret Garden); encouraging, personal correspondence with each child and, yes, PRIZES! (Jordan won two "Dilbert" T-shirts with internet cartoons during one session).
Tell your friends; tell other teachers; tell the public library and the media director at the public school (Tell anybody with $85 bucks for the official dictionary ... including grandparents). Carolyn's Corner can motivate your child to read books, use the dictionary and begin looking at root words and definitions rather than rote memorization of spelling lists.
Karen Mohs is the author of three curriculums in linguistics that are fairly well known among Christian homeschoolers. Hey, Andrew! Teach Me Some Greek!; Alone With God Bible Studies; and Latin's Not So Tough! are on many parents' wish lists. We try not to endorse commercial curriculum sites, but Greek 'N Stuff is an exception.
In addition to several (absolutely free) really fun, interactive "teasers" to introduce her curriculums, this homeschool mom is sharing dozens of classical reference links ranging from the Qumram Library exhibit of The Dead Sea Scrolls to an interactive Latin Vulgate Bible search form. So, when your homeschooler asks, "Mommy...what's the difference between Classical and Helenistic Greek syntax?" you will have the answer at your fingertips!
John Amos Comenius, a 17th Century Protestant bishop and humanist educator, provided the inspiration for a pair of English professors at The New School for Social Research in New York City to develop a group of language arts programs including, Fluency Through Fables. Kids select a short fable, then test their reading comprehension with true/false and matching questions, sentence completions and discussions which are posted on a bulletin board along with the writings of other students from around the world. This is another site which, while offering a commercial product, has provided no-cost interactivity for your homeschooler.
Another great, free site for interactivity (and a dose of homesickness, for us) is The Exploratorium at the Palace of Fine Arts in San Francisco. Using Real Audio plug-ins, a child can "participate" in very cool experiments (Home of the infamous "Cow's Eyeball Dissection." Yuck!).