Lycos50 includes an entertaining account of why the term "Aqua Teen Hunger Force" is the second in their "Movers and Shakers" list, with the story of a panic caused by an ad campaign for the cartoon in Boston (more at Advertising Age).
However, the first place is taken by Groundhog Day on February 1st, again, a holiday. You don't really need a groundhog to tell you that there will be an early spring this year, you can see it in the very mild winter that we experience.
It would be interesting to compare, actually, the two events. One, something traditional, annual, almost boring, known to the rest of the world mostly because of the movie . The second, a guerilla type marketing that worked (if you have the money that Ted Turner has to pay to the city for the scare caused...) . It really depends on your audience: kids and teachers looking for ideas for Groundhog Day? 15-30 males, who are likely to respond well to the commando tactics?