LEGS
Squats (hamstrings, quadriceps, and gluteals):
With feet shoulder-width apart and a barbell balanced across your shoulders, lower yourself until your thighs are parallel to the ground, then raise yourself to the starting position (make sure you don't lean too far forward). That's a repetition (rep). You can also perform this exercise without weights.

Single-leg Calf Raise (calves):
Holding a bench or something else for support, place the ball of one foot or step so that you are approximately two inches off the ground. Raise yourself as high as you can on your toes, then lower your heel towards the ground, then raise yourself again. That's rep. This can be done with or without weights. If you want to use weights, grasp a dumbbell in one hand while maintaining your balance with the other hand.

Dips (triceps):
Support yourself by gripping both sides of parallel bars. Your upper body should be upright, with your arms straight at your sides, and your ankles should be crossed with your shins parallel to the floor. From this position, use your arms to lower yourself, stopping when your upper arms break parallel to the floor, then raise yourself up to the starting position. That's a rep.

Alternating Lower-Back Extensions (lower back):
While lying flat on your stomach with your arms stretching in front of you, simultaneously lift your right arm and left leg off the ground a few inches, then lower them back down. That's a rep. Repeat the movement with your left arm and right leg.

Pull-ups, palm-forward grip (upper back), palm-backward (biceps):
With a wide grip, hang as low as possible from a pull-up bar. Cross your ankles and keep your shins parallel to the floor. Now pull your body up until your chin passes the bar. Lower to the starting position. That's a rep.

SHOULDERS
Lateral Raise (deltoids):
Stand up straight with a dumbbell in each hand. Your arms should be at your sides, palms facing inward. Keeping your arms straight, raise the dumbbells in a 45-degree arc until your arms are parallel to the floor, then lower the dumbbells back to your sides. That's a rep.

ABDOMINALS
Crunches (abdominals):
In a lying position, keep your thighs perpendicular to the floor and bend your knees so that your lower legs are parallel, ankles crossed. Rest your hands on the back of your head for support (don't pull with your hands!) and bend slightly at the waist, drawing your upper body toward your knees. Lower your body back to the floor. That's a rep.

Obviously this is not an exhaustive list of exercises that you can perform. But hopefully its enough to get you motivated and started in the right direction.