Wooden sleepers are essentially pieces of wood that can be used for a variety of purposes. They are often thought of as outdoor materials, however they can just as easily be used in the home.
Think carefully about the types of sleepers you are going to use. This is important because of the finish. Some sleepers have been recovered from railways and will therefore be very tarnished. This may look weathered and pretty out of doors, but it is probably not going to create the desired effect indoors. Think about the look you want to achieve and think about buying new sleepers for internal use.
Think about how you are going to use them. Something like a chunky wooden coffee table, or even a display cabinet, can look really good when constructed from sleepers. If you are not confident working with wood, hire a carpenter or joiner to help with your project.