Split-flap departure board, Gare du Nord
At Gare du Nord, I find this stupendous example of a split-flap display still in use. It's made by Solari, an Italian company, a premier manufacturer of these (as well as the Dator 5 clock I'd also pay through the nose for).
Sadly, like most mechanical things that are awesome to behold, they easily fall into disrepair, and reliable, versatile, dull electronic signs are driving them to extinction. Fortunately, MOMA's going to hang onto one.
As for me and my split-flap clock needs, I continue to make do with this one.