Religious atheists: how much planning/preparation do you put into your religious...

[No Magpie Without Chance]

...holidays? Do you plan far in advance, or do you prefer to "wing it"? What do you find hardest about preparing for a religious holiday or festival? Do you ever invite people from outside your religion to participate with you?

This obviously doesn't apply to non-religious atheists, although I'm willing to bet that it won't stop them from answering.

Thanks in advance.