Pi Crust

This is a PCB that brings sanity to Raspberry Pi headers.

Features

Really compact - sits inside the surface area of the Raspberry Pi and adds less than 2mm to the height. If you have a case for your Raspberry Pi, this board should fit inside it.
Pins are grouped together: GPIO, I2C, SPI, UART and power.
Every pin is clearly labelled.
Connections: 2 x SPI, 2 x I2C, 1 x UART, 8 x GPIO
Uses female headers instead of male headers - you can poke jumpers right in.
Lots of GND and 5V pins - you need those guys a lot. These pins are duplicated where it makes sense (e.g. within the UART, I2C and SPI groups).
All thru-hole components - you can solder it yourself.
Cheapety cheapy cheap.
Open source hardware.
More photos here