SPARK!! Students need to keep active. I have a large, rowdy class that cannot focus; I take them outside with different sports equipment (or for a walk around the school in poor weather), and they come back to class focused and ready to learn. They also start the class more focused because they know Spark is coming. I usually have them write a journal or silent read for the first 25 minutes of class, then we go out for Spark for a maximum of 20 minutes (including travel time), then we come back for about 30 minutes of more class. The break outside of class is worth it, otherwise no work will be done at all during the entire period. The first time I did it, I was SHOCKED at how focused and ready to learn they were when we came back.
My current school encourages teachers to do it in their classes; in my previous school, it was a regularly scheduled part of the day for every student in the school. All you need is somewhere to walk around, and some equipment like a football, frisbees, soccer balls, dodgeballs, basketballs, etc. You could also lead them in other types of exercises.
Look into it:
http://www.sparkpe.org/physical-education/
https://store.schoolspecialty.com/OA_HTML/xxssi_ibeBrandPage.jsp?docName=V700818&minisite=10206
Teaching In Real Life 