No apocalypse here

yes

Huh ok then

I need to know which one now. XD

It's right when they meet Brook (the skeleton)

there are so many episodes so I can't for life remember wich on it is

Episode 337 is where Brook comes. So after it their adventure in Thriller Bark starts. No one should miss the part where Usopp bows and says "Thank you very much" for seeing Nami naked there. XD