The tricep dip is an excellent exercise that works the triceps using your own body weight in a very simple way.
Detailed Workout Plan
Place your hands beside you on the bench with your feet placed out in front of you.
Keeping your back straight and your tailbone close to the bench, lower yourself until your arms are at a 90 degree.
Raise yourself back up to the starting position by fully extending your arms and contracting your tricep muscles. Repeat action.