Ring down the curtain
At first glance, ring down the curtain appears to be a mistake. Should it not be bring down the curtain? Apparently not. Ring down the curtain dates from the late 18th century, and for about 100 years before this, theatres in Britain used to ring a bell at the end of a performance when the curtain came down. Theatres also used to 'ring up the curtain' at the start of a performance or after the interval. These expressions are rarely heard these days, but a bell is still rung in theatres today to indicate that performances are about to start, or re-start after intervals. The similarity between ring down the curtain, and bring down the curtain is purely coincidental. See Bring down/draw/close the curtain.