Exercises to add to your workout.

There're two problems with doing the same workout day in day out. The first is that it's hopelessly dull and the second is that when your body gets so used to doing them it adjusts, you don't work as hard and therefore you burn fewer calories.
So, if you're lacking ideas and exercises to spice up your workout with then here are a few.

Mountain Climbers - A challenging calisthenic exercise which works the core and legs whilst increasing the heart rate.
Begin in a pushup position on the hands and toes. Bring the right knee in towards the chest, resting the foot on the floor. Jump up and switch feet in the air, bringing the left foot in and the right foot back. Continue alternating the feet as fast as you safely can for 30-60 seconds.
http://exercise.about.com/b/2009/04/14/exercise-of-the-week-mountain-climbers.htm

Burpees - A difficult but do-able calisthenic exercise.
Begin in a squat position with your hands on the floor in front of you. Kick your feet back into a pushup position. Immeadiately return your feet to the squat position. Leap up as high as possible from the squat position.
http://www.rosstraining.com/articles/burpeeclip.htm

Jump Squats - An easy calisthenic exercise that will work your legs and keep your heart pumping.
Begin in a squat position with your hands on the back of your head. Jump up quickly with as much power as possible. Land in the squat position again.
http://mrjefffitnessfun.files.wordpress.com/2009/06/squat_jump.jpg

Jumping Jacks - One of the most simple cardiovascular exercises possible that is unfortunately often ignored.

Happy Reading :)