When you're locked out of your home, a trained locksmith can probably open your dead bolt rather quickly. Even though locksmiths know how to pick a door lock, they may recommend other options such as re-keying a lock. Pin-and-tumbler deadbolts have the handy feature of being able to be reconfigured with a new key that is made for the same lock design. This allows you to add more locks in your home without adding more keys.
If you want to make a brand new key for an existing dead bolt, you can start by cutting the key blank with a pattern that matches the positions of the pins. You can also make a lock fit an old key by aligning the pin pattern to the notches of the key. A locksmith can quickly re-key locks featuring a universal keying system, but many hardware stores offer lock re-keying as well.