The Gallery Hotel Art in Florence has a sign that you won't notice in the daytime for it is just a series of metal wire attached to the side of the building. But come night time, a spotlight above lights up and those bent wires cast shadows which spell out the hotel name.
It's a unique lighting choice and cleverly done. On one hand, it saves a great deal of energy as there is only one light. But on the other hand, a day time sign is necessary too otherwise how else would guests find it?