I do my workouts at home. One of my 'staples' is various forms of marching in place, kicks, kick backs, side steps, etc (Leslie Sansone inspired moves).
I saw online this morning a woman talking about how long orchestra conductors live and she demonstrated the arms movements that they do when conducting and she said it would be a good cardio exercise.
I decided to add it to my marching in place exercise and it really helped to get my heart rate up.
Just hold your arms up at a 90 degree angle and then take them up and then out to the side like a conductor conducting music.
I could really start to feel the burn after a while. You might not want to do it in public though