Wouldn't it be a good idea to name one day of the year where we put extra effort into promoting Ubuntu?
btw here is a list of some existing days: http://en.wikipedia.org/wiki/Awareness_day
As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or specific expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, see the FAQ for guidance.
No there is no such day.
For me , i propose 12 April (12.04) to be this day as we'll use this LTS (12.04) many years
All the proposals in the previous answer and comments both in the question and answer itself are really good.
Nevertheless I would go for something more impacting into the technology field of specific places everywhere.
What I want to say is that, a small group of people talking off a specific topic in a city will result in vain efforts or making us being seen as "hippies" talking about "love and peace".
It will result better if we organize local/regional and even nationwide groups who will attend to both local/regional and even nationwide science fairs, conventions and other technological presentations on which people interested in technology will really pay the proper attention to what we are talking about. Even press conferences will result in something better.
Just my humble point of view but based on experiences in the media, doing such a "celebration" results in the people paying attention just once, while organizing for live presentations gives better impact in the proper people.
Unfortunately, the event's dates won't always match Ubuntu's special dates (like release dates).