Happy π day everyone! I hope you’re having a great day, and having lots of fun mathematical parties.

You may have noticed that here at The Aperiodical, we’ve been posting exciting π-related items all week – and here’s a list of them all, collected into one handy place. Enjoy!

### How I Wish I Could Celebrate π

We began by listing approximately τ ways you can celebrate π day, from eating tasty pie to getting an ill-advised tattoo.

### The Aperiodical’s π approximation Challenge

Seven mathematicians; π hours; one transcendental number. How close will they get? Watch this video and find out.

### Matt Parker Approximates π by Weighing a Circle

Jumping on the bandwagon, stand-up mathematician Matt Parker has also attempted to find π by measuring the real world.

### π and the Simpsons

Author Simon Singh has picked out his top three π references in the world’s favourite cartoon comedy series.

### Mandelbrot’s bum is full of π

Occasional guest author Andrew Taylor has been looking for π in slightly awkward places, and has found it somewhere you’d never expect…

### Alex Bellos’ Pi Day Blog Post

Short but sweet, Alex sent us a little something towards our celebratory π day post-fest.

### π and the mysterious Excel function

Regular guest author and pendulum-wielder Paul Taylor spends a lot of time at work using MS Excel, and has dug into its deepest darkest corners to find a function he can’t immediately explain.

### How Ultimate is Ultimate π day?

Aperiodical editor Katie Steckles doesn’t believe the hype, and reckons that while today’s date is exciting, we can do better.

### π, Phase Space and Bouncing Billiard Balls

Friend of the site Colin Wright has found π in yet another place – when balls collide.

### π and Constrained Writing

Katie explores the world of making your English homework arbitrarily more difficult for no reason.

### Interesting π Esoterica

Christian’s Interesting Esoterica column, always a trove of intriguing finds, has gone π-themed, with typically fascinating results.

### I Bought three.onefouronefivenine.com

Christian’s obsession with purchasing novelty domains turns π-shaped.

### π approximation: Machin’s Formula

Peter joins in the π approximating fun, using a Maclaurin series.