Lucidscience is showing how to drive a VGA screen using an AVR microcontroller. The process is quite simple and requires only a few resistors and diodes. The first implementation has a 56×60 pixels resolution and the second version has 240×240 resolution along with double buffer to make animations smoother. The project is well documented and you can see schematics and photos on the link below.
AVR microcontrollers to VGA interfacing – [Link]