This one called, "Magical Capitals" is terrific for second and third graders. There's LOTS of great grammar games on this site!
If you haven't found Sentence Monkey yet, don't wait another minutes! LOTS of games that practice grammar skills (by skill). Games are easy to play as they are "drag and drop". This is a really good one for centers!
This is a terrific activity for a center/station. Students click on different parts of speech and get immediate feedback! There are four great games here!
I LOVE this site called "Grammar Bytes"! You do need to register, but it is free. Once you are registered you get free handouts, presentations, videos, and tips. What a find!
This terrific site has games for second, third and fourth graders that include contractions, kinds of sentences, spelling, grammar and more. The game shown is "Sentence Clubhouse". Kids build a clubhouse piece by piece by answering questions about sentences.
And of course, Grammar Gorillas!
What grammar sites have you found that work well? Add them in the comments section! I'd love to visit your favorite sites!!