http://en.wikipedia.org/wiki/Singles_Awareness_Day
Singles Awareness Day (SAD) is a humorous holiday celebrated on February 14 (although some prefer the 13th or the 15th to get away from the commercialism associated with the 14th). It serves as an alternative to Valentine's Day for people who are single; that is, who are not involved in a romantic relationship and can therefore not participate in Valentine's Day traditions. Some observers of SAD do so out of spite for Valentine's Day, as a Hallmark holiday, or for other reasons.
On Singles Awareness Day single people gather to celebrate or to commiserate in their single status. Some want to remind romantic couples to remember those less fortunate than they are. A common greeting on this day by its adherents is "Happy SAD!"
Sadly, the day is often used by less friendly couples as a day to simply remind the singles they know about their current, uninvolved status.
The holiday is a good example of self-deprecating humor.
