It's May 5th, also known as Cinco de Mayo!
According to Wikipedia:
The date is observed to commemorate the Mexican army's unlikely victory over French forces at the Battle of Pueblaon May 5, 1862.
With the Mexican festivities, I thought it would be fun to incorporate cute little Pusheen with a sombrero, a wide-brimmed hat in Mexico!
Isn't he the cutest? :D