i appreciate your idea of wanting to develop a culture to make esperanto more attractive. but not everyone will be attracted to it because of the parties, it could also turn some people off.
i guess most of us want esperanto to appeal to everyone, and developing a new unique culture may or may not be the right approach to that. i could be wrong, but any culture has a tendency to attract only a subset of people (those who like that culture).
this doesn't have to be bad, that subset could be just what is needed to spread esperanto to more people, or it could have the opposite effect.
i am not suggesting that inventing new holidays will make esperanto look strange. it's probably more like a sports club or some other activity that has developed their traditional events for whatever reason.
i guess my feeling is, that this won't make esperanto stand out to much, and it won't aappeal to people who don't like parties.
so instead i'd like to turn your suggestion around into a different one:
embrace local culture. think about who you want to attract to learn esperanto and adopt their holidays and celebrate them in esperanto.
an esperanto church service to invite your christian friends to.
an esperanto computer party, where you help everyone get proper esperanto language support on their computers. you can invite computer geeks to help with the technical issues while exposing them to this concept of the esperanto language.
celebrate the founding day of your city/country.
do social projects (like teaching esperanto to underprivileged people. (esperanto is so easy to learn, it will boost their self esteem and enable them to make friends worldwide which will help them to see a world beyond the local environment they are stuck in))
pretty much any event that your friends would go to, but with an added twist that it's done in esperanto.
the idea is that instead of inviting people to move to a new country and experience a new culture, show that esperanto can be part of their culture, that it can be used to help with local issues, and that they can learn it without changing anything else in their lives.
ni estas esperantoj.
via kultura diferencigo estos aldonita al nia propra.
rezisto estas vana.