Meat features prominently in many holidays worldwide. Here is an example from Chile of how veg*n activists are seeking to start new traditions. In Chile, the country's independence from Spain is celebrated on 18-19 Sep, with meat eating playing a major role.
To begin a new way to celebrate their country's independence, activists in the Chilean Vegetarian Vegan Society created a party with much the same food, but the vegan versions. They call the event the 'Fonda Vegans del Huaso Vegetariano' (loosely translated as The Vegan National Independence Day Party of the Chilean Cowboy). The first fonda was in 2006, and it was such a success - with lots of people attending and lots of media coverage - that it has been repeated every year since.
Here you can view videos and photos (text in Spanish): huasovegetariano.blogspot.com