How to Connect multiple Ping))) sensors to uno R3?

Recently i saw a robot with about 20 ultrasonic sensors all around. I found that multiple sensors can be connected through I2C ports(A5 & A4) with just 2 wires to arduino. there are many examples for i2c connection to LCD and accelerometer. but not for Ultrasonic sensor.

So my question is,

Can i connect multiple ultrasonic sensors using I2c. if yes how?
is there any other possible way to connect 20 sensors to 1 arduino uno R3?

Does the Ping))) (or any other cheap ultrasonic sensor) operate using I2C?