Funny Pi rate Pi Day Humor T-shirts. Funny Pi-rate shirts and gift ideas for those that celebrate Pi Day every day and more specifically honoring Pi Day on March 14th at 1:59 PM- that's 3.14159... Pi Day should never end. Featured is Pi as a swashbuckling pirate armed with eye patch, sword, peg leg and of course a parrot. Our Pi-rate Gear makes a great gift for your math teacher. Math teachers can also give Pi Day stickers and Buttons to students.