Warming up the body is important before any major workout.  It gets your blood flowing and loosens up the muscles.  The biggest proponent to warming up is encouraging range of motion, limbers up the body, and helps to prevent injury.
Round One – 5 minutes
Start off by getting full range of motion for each area below.  Spend as much time as you need to make sure you are fully comfortable with these joints.
Neck Rotation – Rotate the neck slowly providing full range of motion of your neck.
Hip Rotation – Rotate clockwise and reverse providing full range of motion in your hips.
Knee Rotation – Rotate your knees with your hands above the knee caps and rotate slowly.
Ankle Rotation – Slowly rotate each ankle separately allowing full range of motion within the ankles.
Arm Rotation – Finish the rotations off with the arms by rotating small circles, and then gradually increasing the radius to a full swing.  Repeat by going in reverse direction.
Round Two – 10 minutes
Now it is time to get the heart rate up and the blood flowing.
Hops – Just start hopping in place as you would in the ring before a fight.  Focus on staying light on your feet with light movements.
Jumping Jacks – Start doing the side straddle hop.
Running in Place – Start running in place.  Get your knees up high so your quads are parallel to the ground.
Run – Start jogging.  If you are outside, run for a good minute and a half.  If you are inside, run the circumference of the room.
Side Shuffles – Work on your footwork with the side shuffle.  Focus on going both directions.  Go for 1 minute.
Pushups – Start performing pushups for 15 seconds.
Plank – Perform a plank for 15 seconds.
Power Squats – Perform a power squat for seconds.  Execute a squat, and when you come up, hop and bring your feet together and repeat.  Go for thirty seconds.
Last Round– 5 minutes
Finish your warm up by performing stretches of your arms and legs.
Conclusion
Adjust the times based on your skill level and go at your own pace.  This warm up should definitely get your prepped for any intense workout you will face.  Comment on this warm up and let me know how it works for you.