Everyone always talks about using "authentic" writing pieces in the classroom to teach grammar and that students do not learn grammar by doing worksheets. Depending of course on the students you have, I believe that using a combination of both is very beneficial. I believe it is important for students to practice the grammar after they've been introduce to it, in order to consolidate their learning.
I love using the good ol' "Comptines" to teach grammar - the kids love them! I pick a Comptine that has grammar components that I want to teach/introduce to the class, and we get real silly about reading them. Sometimes we add actions, other times we whisper-read it or try to read it with really goofy voices. After having read it a couple of times, I close the book and see who has memorized it. They LOVE trying to prove that after only reading it a couple of times they have it memorized. It's great because not only do they have fun learning grammar, they also get practice speaking proper grammar! :)
So after we learn our Comptine, I have students go to the Le Point de FLE website and practice what we've learned. This website may seem overwhelming at first, but once you get familiar with it, it's got amazing (and fun!) resources for students. Some are listening exercises, which they love doing as a class, or, you can send them to the computer lab and have them do it on their own.
I would love to know if you have other "must-have" French Grammar websites!