Every year a slightly covert organized Flash Mob takes place in Paris...Le dîner en blanc. It is hard to get invited since all the planning is done in secret due to taking over some public place. But I managed to get invited one year.
In short, groups of people dressed completely in blanc all meet in slightly hidden areas of Paris (in parking garages, in galleries, etc). They are not only dressed in blanc but have a table and two chairs. They even recommend that you try to bring food that is blanc, along with the champagne and white wine, of course.
Then at the appointed time everyone descends upon a location in Paris all at the same time and sets up. There were even buses of people that arrived from locations further out in Paris. This is illegal, for sure, but what can the police do when a Flash Mob of 10,000 people sets up to eat dinner where they please?
One year they did this at Invalides. The next at the Arc de Triomphe. Then the Champ de Mars (Eiffel Tower). We did not know where it would be the year I was invited. It is a highly held secret by the organizers. We were told 5 minutes before we had to walk there from our 'hiding spot' (meeting point) at Madeleine (though we had kind guessed where bsed on the hiding spot). The year I went it was at Place de la Concorde (Concorde Square) square next to the Tuileries garden and Louvre Museum
If you have seen this plaza you know how ginormous it is. Imagine throngs of people just converging on it suddenly with their tables and chairs. The organizers were extremely prepared, including maps of where they were supposed to set up, and all the tables are put down in long rows. Women sat on one side of the row and men on the other. It was controlled to perfect French style.
We took over Concorde!
Within 15 minutes there were 10,000 people in blanc sitting down to a blanc dinner at Place de la Concorde! It was truly an amazing site.
The cops drove by a couple times bleating their sirens at us. In response everyone stood up on their chairs and began to cheer and spin their napkins in the air above them in haughty defiance.
Then after dinner, exactly at 11pm, everyone lit sparklers. Yes, everyone. ~10,000 sparklers all lit at the same time and waved about. Then the music started! There were bands, and DJs; it depended on your section. This is one of the coolest things I've ever done.
The upside is the amazingly friendly atmosphere and extremely good organization of such a complicated event, as well as the fun you have in the process of defying French authority.
The downside is that couples of men and women only were allowed, which means that singles and same-sex couples are out - I dearly hope they've since changed that rule.
The White Dinner Official Website: http://www.whitedinner.fr/
How to get invited? It is very hard. You must know someone who is organizing a section at it, and they can each only invite 10 people...