The first few days of school really are the most important days for both teachers and students; it is the time where the culture of your classroom is created. To help you and your kids develop that culture, I have a few ideas that may help!
May I suggest you begin with doing some class building experiences. You can find some GREAT ideas at these two websites!
Here is a great idea–a survival game, check it out here!
May I also suggest interest inventories. There are a plethora online!
Enjoy this time learning about students!