NovaVGA is a low-cost shield board for the Arduino that provides an easy-to-use VGA graphics output. The adapter is controlled via a simple SPI interface from the Arduino (or any SPI-compatible microcontroller.) 

NovaVGA keeps a 160x120 frame buffer in SRAM and outputs it to a monitor at an industry standard 640x480 @ 60Hz VGA signal. 

Complete specs at the NovaVGA product page.
Note: NovaVGA does not include header pins.