what are the colors for?

I love those moments when you're shuffling along with the rest of the herd, headed home from a long day of work, and you look up and remember where you are.  I took this last night on my way to Grand Central, I'm right by Bryant Park with a great view of the empire state building.

But I couldn't figure out what the colors were for.  They look like a flag to me, is it some country's independence day or something?  Is there a place where you can check the schedule of colors for the empire state building?  It's one of my favorite features of the nyc skyline.