You would think everyone's birthday appears in Pi somewhere, but there are some some simple sequences that don't show up, or not often. The number 123456 doesn’t appear anywhere in the first million digits of Pi. Using Find Birthday in Pi, I found 12-3-45 at position 49,703. It doesn't seem like it would take almost 50,000 digits for 12345 to show up but it did.
Rounding the number Pi to just 9 digits after the decimal point, and using it to calculate earth’s circumference yield incredibly accurate results. For every 25,000 miles, the number Pi will only err to 1/4 of an inch.