The 74HC164 is a 8 bit serial to parallel shift register. It is exceptionally useful when you need to expand your inputs. This allows you to convert 1 serial byte into 8 outputs. The 74HC164 also allows you to cascade these devices for more bits. You will need three pins, serial and serial clock. The 164 does not have a latch so if you are using ti to drive LEDs you will see led flickering as the bits are shifted.
Spec Sheet: http://www.ti.com/lit/ds/symlink/sn74hc164.pdf
Voltage In: 2V ~ 6V
Supply Current: <80uA
Current Output (Max): mA
Output Type: Tri State