As per Wikipedia Valentine’s Day is
Saint Valentine’s Day, often simply Valentine’s Day, is a holiday observed on February 14 honoring one or more early Christian martyrs named Valentinus. It was first established by Pope Gelasius I in 496 AD, and was later deleted from the General Roman Calendar of saints in 1969 by Pope Paul VI.
Google is celebrating the day Valentine Day that is 14th feb, 2012. Have a look at the Home Page of Google.