described on the Ben & Jerry's web site:
Is there a better way to say "thank you" than with free ice cream? We think not! That's why every year, since our first anniversary back in 1979, we have grabbed our scoops and invited fans of all ages to join us for Free Cone Day.
What is Free Cone Day?
Well it’s our way to celebrate and say thanks for another year of support, and we’ve kept it up every year since, spreading the peace, love & ice cream around the globe!
Between 12 p.m. to 8 p.m. on April 10, Ben & Jerry’s scoop shops around the world will be giving away free ice cream to customers in celebration of their 40th annual Free Cone Day. (You can use this list to find the scoop shop closest to you.)
The history of Free Cone Day is reviewed in the following video: