Wouter van Ooijen runs VOTI is an engineer who has worked on many software and systems projects. He has a Webshop with PIC Parts and Kits. His PIC FAQ and “blink a LED using one of these flash PICmicro controller” is great for beginners.
A circuit that generates a voltage that rises slowly from 0 to 10 Volt and (when a switch is flipped) slowly back to 0. The request did not pose much restriction on the wave form, but a rise / fall time of 30 minutes should be possible.
I got a mail question, which i logged here Long Duration Linear Sweep or Ramp Generator. The above project could be an neat answer.