There are always the
DPS Assignments 
. I am trying to get into the habit of shooting a new picture for each assignment rather than just relying on photos I have taken in the past - that makes it more of a challenge and more of a learning experience.
I also find it useful to have a camera to hand - for example, I spent three hours yesterday afternoon learning how to cut a small hole through a piece of stone (see
my blog for details) but at least I got some interesting photos from the experience, like this one:
Since I was working on a circular stone, I also tried to get some shots that might allow me to make another entry for the
squared circle group on Flickr (another example of motivation from having somewhere to share new pictures). I was particularly pleased with this one:
It has not been trimmed down to fit the requirements of the group yet but the patterns and colours suggest a mosaic to me... and I'm off with another idea to riff on next time my camera is to hand
Wulf