David designed a home-built AVR in-system programmer. It’s built on the USBtiny and V-USB firmwares and uses a ATtiny44 microcontroller to communicate with avrdude over USB and a target microcontroller over the 6pin IDC cable.
The FabISP is an in-system programmer for AVR microcontrollers, designed for production within a FabLab. That is, it allows you to program the microcontrollers on other boards you make, using nothing but a USB cable and 6-pin IDC to 6-pin IDC cable. It’s based on the USBtiny and V-USB firmwares, which allow the ATtiny44 to perform USB communication in software. Programming can be done through avrdude.