Whenever working with the GPIO ports of your Raspberry Pi you face challenge to remember which pin corresponds to what. E.g. which pins do I use when connecting a SPI device or where do I find the GPIO #17 pin?
To assist this I have put together a printable GPIO Card you easily can fit directly on your GPIO header. Although initially made for the 40 pin GPIO header of the A+, B+ and the version 2 model B boards, you could easily fit it on a version 1 model B rev 2 board as well (simply ignore the last 14 pins).