Looking for pi resources

Planning a unit that integrates math with other subjects has been causing me some strife because I usually think of math as something separate which might have some minor connections to other subjects through word problems but that might only be coincidently.

But with this unit, I want to really integrate the math and have my students think about why a circle has been used for consensus building and how different forms of government have used different structures and why.

I want my students to really think about form and function, but to also really understand how circles are related to each other mathematically.

It's a balancing act.

So far, I've found a song about pi:

And this video about the history of pi: 

but it's a bit dry, I might not show it all. 

And there are whole websites devoted to poems about pi.