The last day is always problematic. The event ends at a specific server time - eastern standard time. I live in the eastern time zone - events end and start on that appropriate data at the specified time. Depending on where you live you get completely hosed up.
For example, the original end date is January 1, 2012. If the end time is zero hundred hours, I will not get any use out of the first. Same thing if the end time is 3 am or even 8 am. I do not remember what time during the day these events end. After all the complaints they might be using midnight on January 1, 2013 which would mean it would be up on January 2, 2013 for people in Europe. You have to consider when the quest reset. I think they reset at 3 am eastern.
Perhaps someone that has kept better track of the "exactly" can help you out. Due to Turbine's issues with time, I never plan to get anything done for the festivals on first or last day.
Unless stated otherwise, all content in this post is My Personal Opinion.