BD is a French holiday, but can be celebrated by anyone. It celebrates French's democracy!
On PD, do not let total chaos bring you down! Keep calm and sane and stuff!
NND probably has something to do with Nude Recreation Week! Basically, you, erm, take it all off. I'll just straight out say I WON'T be participating in this holiday that much. ^ - ^ But hey, I wear no makeup! That's au natural enough, right??!