Just this week we updated our Squidoo lens - Dog Holidays - for 2013. It lists a wide variety of dog related holidays including Responsible Dog Ownership Month, If Dogs and Cats Had Opposable Thumbs Day, National Scoop the Poop Week and many, many more.
We've also added instructions for adding these holidays to your Google calendar.
It's a great resource and will save you hours of time.
Image courtesy of Brandi Jordan.