I joined the Spitpainting group on Facebook, and I have to say, it has been the single greatest source of motivation and inspiration for me in a long while. The group's premise is very basic: 1.) 30 minute time limit to finish your painting 2.) NO phototextures whatsoever. New topics are posted daily, and they are generally very vague.
Here are a few of the paintings I submitted to the group!
A thing for Halloween...
And here's some freelance designs: