I find hacky sac is an excellent way to "do cardio".
It gets your heart rate up and also greatly increases your balance and leg coordination.
The time flies by and before you know it you've spent a couple of hours kickin it up.

Can you hack it?
-Pete.

__________________
"The pain of life should burn with unquenchable fervor, unyielding in life’s entire eclectic array of stations."