Sun Yat-sen once plotted the overthrow of China’s last dynasty here at number 36, and during Prohibition, this was the site of turf battles over local bootlegging and protection rackets. Spofford has mellowed with age: it’s now lined with seniors' community centers. But the quiet alley livens up around sundown, when a Chinese orchestra strikes up a tune, mah-jongg games begin with a cascade of clicking tiles, and barbers and florists use the pretense of sweeping their doorsteps to gossip.