IDUINO Prototype Shield

The Arduino Prototyping
Shield makes it easy for you
to design custom circuits. You can
solder parts to the prototyping area to create your project, or
use it with a small solderless breadboard (not included) to
quickly test circuit ideas without having to solder. It's got extra
connections for all of the Arduino I/O pins, and it's got space
to mount through-hole and surface mount integrated circuits.
It's a convenient way to make your custom circuit and Arduino
into a single module.