P.E. and Math
Most everyday my kids do a sheet of math facts practice (like Saxon or Calculadder). They were getting rather tired of doing this. To make it less tedious we are mixing it with a little physical activity.
I give the problem 6×4 and throw a ball to them. They throw the ball as they give the answer. Simple, but fun.
Sometimes we do exercise. For every row we do a different type of activity. It may be leg stretches, push-ups, jumping jacks, running up and down stairs, putting our arms straight out from our sides while turning them in small circles -whatever I can think of. 
We even use a stopwatch sometimes to see if they can improve on the previous days times.
Just a humorous side-note.
Yesterday my son WE, who tends to not like exercise overly much, was saying his arms were too tired to turn them in circles anymore, (there were only 6 problems) so ZJ took some straight pins and held them underneath his arms to give him an added incentive to keep going. After this occurrence were considering a more rigorous physical education program for our homeschool.