Cover As Much Ground as you can, as fast as you can ( run Walk ) for 3 mins straight line distance.
Then Put your arms straight out in front of you, and march in place for 2 mins, as fast as you can, getting your knees as high as possible.
Then go back to your start of the 3 mins, as fast as possible.
for the remainder of 10 mins
Sit down on the ground and stand up ( should be around 2 mins of work)
fun.... simple...and super effective..
no gym, no problem!!!