Some Buddha's consider this the date of Buddha's Enlightenment (His Great Awakening) as well as his physical Birthday! I like what I've read about the Buddha. His quest for an end to Suffering!
I like that fact that the Buddha just means that he was the Enlightened one! The one who figured some things out! Simplified, I know, but Cool Beans!
BE Prayerful! BE Mindful! BE Careful!