There's Valentine's Day here in Japan too. But not quite the same. In Japan, it's the GIRLS who give the boys chocolate on Feb. 14th. And not just to someone they like. There is a uniquely Japanese characteristic of giving "Giri-Choko" -- giving chocolate to the men one would rather see skydiving without a parachute -- the boss, namely. "Giri" means obligation, but in Japan it has a deep sense of long-term committment.
Since gift-giving is a common custom in Japan, many confectionary companies also try to push their own manufactured celebration, "White Day" on March 14th, where it's the boys turn to give the girls something. This attempt has been at best a limited success.