Towards the end of the school year, I was substituting in a great third grade classroom. We finished all the lesson plans with about 30 minutes left in the school day. I wanted to fill the time with something productive, so I went to my go-to lesson... writing. Not having any materials prepared, I handed out notebook paper. The students peppered me with questions of what we were doing. I simply told them "writing," and was met with a chorus of moans. Then I wrote a crazy prompt on the board. I used something like, "Tell about the day you walked into your classroom and found out your substitute teacher was a gorilla." I got questions about how long it needed to be, would it be a grade, etc. I told them the only rules were to write, be creative, and have fun. I was surprised with what happened next. They all started writing and laughing, wanting to share what they had written. I let as many as possible share with the class and was entertained by their creative stories.
I substituted in the same classroom again not long after that. When I walked into the classroom, many of students asked if "we could do more of those fun writing games." I realized with time crunches and testing parameters, students don't get much of a chance to go crazy with their imaginations... and they LOVE that! If teachers can get students excited about writing in any way, maybe great test results will come easier.
So, if you have time to fill or want to build eager students... JUST WRITE!