One of my favorite workouts for metabolic conditioning is to combine kettlebell training with bodyweight training. Bodyweight exercises help round out a solid conditioning program and work very well with kettlebells.
Here is an example of a circuit training kettlebell/bodyweight workout;
Explosive Pushups 1x5 (launch off the floor as high as you can on each rep. great exercise to do at the beginning of a workout to get your nervous system ready)
Alternating Renegade Row 1x8 each side (hold the top position for 1 second on each rep and avoid excessive rotating)
Double KB Lockout Press 1x6 each side (lockout one bell and complete six reps with the other arm. Switch sides and repeat)
Low Position Lunges 1x12 each side (stay low and walk across the room for a total of 12 steps each side. Great quad exercise that I picked up from strength coach Mark Philippi)
Double KB Swing 1x12 (swing the bells outside the feet to chest level)
Pull-ups 1x7 (hold top position for 1 second on each rep. Pull from a dead hang)
Hindu Squat 1x25
Hanging Leg raise 1x8 (2 second negative on each rep)
Take 45 second breaks in between each set and one-minute breaks at the end of each workout.