There are hundreds of different exercises you can do with free weights and resistance machines or with just your body weight to build up muscles. You should include mainly multi-joint compound exercises in your workout as they build muscle fastest. The most popular and effective of these are: dead lifts, squats, bench press, pull ups, shoulder presses and rows.
Whilst they are very effective your body needs to be constantly challenged in new and different ways if your goal is building lean muscle mass. For some reason theses following exercises are often overlooked which is surprising as they are real mass builders. For variety every now and then try and include them in to your routines. new reasons for your muscles to grow and the prevention of boredom setting in are achieved by adding variation to your workouts.
For calf muscles try running on the sand, skipping or donkey raises. Running on the sand is very taxing and the bouncing motion in skipping will provide a real burn. Calf muscles are often stimulated into growth more by more endurance related training as that is what they are primarily used to. Donkey raises are when you place your toes on the edge of a 3-4 inch high block bend over to 90 degrees at the waist and rest your hands on a bard or bench at that height. A training partner or two then jump on to your back and you raise your body up and down by flexing your calf muscles. This exercise is more difficult than the usual machine calve exercises as you have to use stabiliser muscles to keep you steady whilst performing them.
Can you remember the last time you performed dips to hit your chest muscles? A classic mass builder for the chest muscle is dips which are an awesome workout for triceps too. For this exact exercise many older gyms have parallel bars. Often a v shape is formed which provides scope for different grips. This means you can really hit different areas of the chest and triceps effectively.