Deir el Qamar ("Monastery of the Moon") is a scenic little town on the road between Beirut and Beiteddine in the Chouf Mountains. It served as the capital of Mount Lebanon from the 16th to the 19th century and has some of the best-preserved traditional architecture in the country -- stone houses with red-tiled roofs, old churches, a Druze palace and a central square lined with historic buildings.
The town is small enough to explore on foot in an hour or two. It is usually combined with a visit to the Palace of Beiteddine, a few kilometres further up the road.
Nearby is Castle Mousa, built single-handedly by a man with an obsession for all things medieval. It is not historically authentic -- think Neuschwanstein crossed with a folk museum -- but it is entertaining and children love it.