It can be tough to hammer a nail into a hard surface without bending the nail. Lifehacker reader Simoniz points out that a cork can easily help you avoid bent nails.
To hammer a nail in a hard surface without bending the nail, use a cork. Simply stick the nail in the middle of the cork, and then slowly hammer it down (see the video above). When the nail is in the cork, use a utility knife to cut the cork. Finish the job by gently hammering the nail the rest of the way in.
How to sink a nail in a hard place without bending [WonderHowTo]