What is the best type of Cardio?

Taken from my own perspective. Not advice. 

1. Sex.

It doesn't have to be but...

2. Cardio you see when watching the Olympics

Certainly the easiest kind.

3. Race walking

4. Swimming

Depending on duration and intensity

5. Cycling

6. Calisthenics

Ah, the memories of gym class

7. Aerobics

Lots of different styles and levels of intensity in this broad category.

8. K9 Agility competition