I2C is a wonderful interface. With four wires and only two GPIOs, you can connect a whole lot of sensors and devices – in parallel, at that! You will see I2C used basically everywhere, in every phone, ...
Several of the Mid-Range Enhanced Core PIC16 microcontroller devices have a Master Synchronous Serial Port (MSSP). The MSSP module can be used to implement either I2CTM or SPI communications protocol.