Okay, I have some of the best cardio building exercise you can get. And you can do it anywhere.
step 1: put on shorts, tee shirt, comfortable yet supportive undies.
step 2: grab your ipod/zune/w.e for music
step 3: stretch
step 4: start walking out side in any direction you wish for 2-3 minutes then pick it up to a full jog and push yourself accordingly.
Wah-la!
Pro Tip: drink lots of water and eat before engaging in strenuous activities.