Okay, it's a mess-- but it's a functional mess! (As soon as I get a chance, these will be replaced by a nice set of printed circuit boards.)
This set of electronics controls the 3D fabricator. On the left is a Make Controller, which is actually just being used as a super-fancy four-channel servo controller. In the middle, towards the back, the X and Y axis servo motor driver boards are marked by their large heat sinks. Each of those has an AVR microcontroller that accepts a position command, decodes the quadrature signals from the encoder wheels that are on the motors, and controls the high-current output driver (on the heat sink). The two protoboards closer to the front are (left) a third AVR-based controller that controls the hot air heater through a solid state relay, and (right) the PCB from a standard hobby servo, modified to drive a relays that control the automotive jack that drives the Z axis of the printer. On the far right is the solid state relay for the heater, and behind it is a control box with the power relays for the Z axis.
Read more about the Evil Mad Scientist Laboratories 3D Fabricator Project here.