Funbrain has great grammar games for kids grades K–8. My favorite game is The Grammar Gorillas. There are two levels of play: beginner (selecting nouns and verbs only) or advanced (identifying all parts of speech). If you click on the correct word in the sentence, the gorilla gets a banana. Since there are so many games on Funbrain, you may want to go to this website, which lists their games sorted by grade level.
LearningGamesForKids is a great site that has both spelling and vocabulary games for kids in grades K–6 (there are math and geography games too!). For spelling games, you can play classics like Hangman and Word Scrabble or new and fun games like Bouncing Letters. I also like the way the vocabulary games are grouped by type of skill: contractions, compound words, parts of speech, homophones, suffixes and synonyms. I wish I had known about these games when my son was younger. He has dyslexia and struggled to read for years, and many of the vocabulary games remind me of the exercises his speech pathologist gave him. For example, the Homophones matching game is a memory game where you match words that are pronounced the same, but spelled differently. As you click on each word, it gives the definition, and you can play to beat your previous scores.
FunEnglishGames has four grammar games sorted by punctuation, conjunctions, prefixes and suffixes, and verbs and nouns. The games are appropriate for elementary school-aged children and offer interactive and fun ways to learn. My daughter loves the punctuation game, which has a hose that she can aim at the spots of a sentence that are missing punctuation. She has a great time shooting the correct punctuation marks at the sentences!
PlayKidsGames offers 20 games for different types of vocabulary words. Most games are sorted based on grade level. There are several variations of Word Scramble, but my favorite is Vocabulary Pinball. It's a video game version of pinball, but when you get the vocabulary question correct, you get extra balls to play! The site also has games for science, social studies, geography, health and more.
5. Spelling City
Spelling City has over 35 games for spelling, grammar, vocabulary and writing. There are even games on alphabetizing and unscrambling a sentence. I especially enjoy the feature where kids can type in a word and hear it pronounced, which I know will come in handy as my kids add new words to their vocabulary!
6. Grammar Ninja
Grammar Ninja is a fun game for kids to play to help them develop a working knowledge of the parts of speech. Grammar Ninja has three levels of play. As long as you answer questions correctly, you continue through the game—but answer incorrectly, and the words explode!
7. Mad Libs
Mad Libs offers a free app with an entire book’s worth of Mad Libs for kids. I don't know any kid who doesn't love Mad Libs, and the best part is they don't even realize they are learning and improving their grammar skills while they play! If they accidentally place an adjective for an adverb, when they read the story they wrote, it won't make sense and they'll begin to learn the difference. There's no age minimum for Mad Libs, but they are probably best for kids in fifth grade through high school.
FreeRice allows you to learn and help others at the same time! There are many different games to play: vocabulary, grammar, math, SAT prep, chemistry, humanities, geography and language arts. The games are designed for older kids (middle school to college) and adults. For each question you get right, 10 grains of rice are donated to the World Hunger Programme. It’s fun to watch the bowl fill with grains of rice as you get correct answers. My coworkers challenged each other to see who could donate the most bowls of rice! You can sign up to join a group and compare scores, but you don't have to sign up to play. And what a great way to justify playing games for a few hours—you can just say, "I was feeding the hungry!"