This, as opposed to most of the cheap sex sells crap that comes out of Mexico, is what marketing is all about. Simple, smart, creative and uses humor intelligently. The joke is even directly linked to the value proposition of the end product.
Gotta love it:
Hey everyone, happy Pi Approximation Day!
Pi Approximation Day is held on July 22 (or 22/7 in day/month date format), since the fraction 22⁄7 is a common approximation of π.
So go out and celebrate. Transform everything into radians and show that you think this awesome number kicks ass!
Yes, this is real. People actually celebrate this day.