So, I discovered what my wiring issue was! I was wiring up to A4 and A5, as per the Arduino Uno instructions. Turns out, according to this post, that I needed to use D0 and D1. So now the demo code works! 
So, I discovered what my wiring issue was! I was wiring up to A4 and A5, as per the Arduino Uno instructions. Turns out, according to this post, that I needed to use D0 and D1. So now the demo code works!