The installed PiDP-11 I/O Expander Each expander board gives you 16 GPIO pins which can be accessed over I2C, including support for interrupts which has been connected to GPIO 19 on the Raspberry Pi.

There's a joypad controls turn it into a Gameboy-style game machine, a hardware keyboard turns it into a Blackberry-like handheld computer, and a GPIO breakout board promises things both exotic ...