I am looking for cardio alternatives to running, which I find incredibly boring so it's difficult to keep a routine up. I would like something that is a bit shorter and more intensive. I have tried burpees, which are great but I want 1 or 2 more alternatives to switch it up a bit. I am fairly active in general, weight training and rock climbing 4-5 times a week.
Goals I want to achieve from cardio are:
1) Improved stamina on long hikes when I go rock climbing and carrying gear
2) Burn a bit of fat which is beginning to accumulate in my belly area (I am 27, 185cm and 160 lbs, so I'm fairly lanky)
Any suggestions which can accomplish the above but is less monotonous than running?