Pushups (Close and Wide Hand Positions)

How to do it

Lie on the floor face down and body straight with your toes on the floor and the hands wider than shoulder width for a wide hand position and closer than shoulder width for a close hand position. Make sure you are holding your torso up at arms length.
Lower yourself until your chest almost touches the floor as you inhale.
Using your pectoral muscles, press your upper body back up to the starting position and squeeze your chest. Breathe out as you perform this step.
After a second pause at the contracted position, repeat the movement for the prescribed amount of repetitions.

What muscles does the Pushups (Close and Wide Hand Positions) work?: Mainly the chest, with help from the shoulders, triceps.
What equipment do I need?: Nothing but your bodyweight.
Is it good for beginners?: Yes, it is rated beginner level.
How do I track progress on it?: Log each set and beat the weight or reps from last time. Liftrung shows your last set beside the next one and estimates your one-rep max from your sets.

Exercise descriptions: free-exercise-db, public domain.