Ever tried out Facebook Lexicon? It's a nifty tool that looks for occurrences of certain terms on Facebook users' walls and creates a graph that shows how often the term is mentioned over time.

The Lexicon has been around for quite a while now, but while playing with it today I noticed an interesting occurence, which you can see in the image below. Terms like "happy birthday," obviously, are mentioned pretty much all the time, while "Obama" has had a huge spike during the presidential elections and the subsequent victory of Barack Obama.

However, the term "sex" has an unexplainable spike on Friday, May 30th of 2008. Perhaps it's just a glitch, or maybe I'm missing something obvious, but I can't for the life of me remember why people would mention this word more on that particular day than any other day.

Any ideas that can solve the mistery?