Compute 30000 Digits of Pi (π), as Fast as Possible
Python 2 (Spigot Algorithm)

This is just Jeremy Gibbon's algorithm implemented in python. Definitely will be faster once someone else implements this in another language. Other methods might be faster too since I started working on this when the rules stated that I could only use integers. I originally tried doing this without string conversion and joining, but it was actually slower..

def p():
 q,r,t,j=1,180,60,2
 while True:
    u,y=3*(3*j+1)*(3*j+2),(q*(27*j-12)+5*r)//(5*t);yield y;q,r,t,j=10*q*j*(2*j-1),10*u*(q*(5*j-2)+r-y*t),t*u,j+1
p=p()
print''.join(str(p.next())for x in[1]*30000)


Completes on my work machine in about 53 seconds.