I had my cell phone camera out playing around recently. I believe I wrote it before, but it is really good to keep in practice. You even make some pretty interesting images goofing around with these things. One of my favorite images of the year was made with the phone. I really like this line of shopping carts there. Too bad I can't make reasonably sized print of it!
One thing I like to do with these is play quite a bit in post with them. I'm not super good with post-processing. Sure, I know how to pull sharpness into the image. I can clone out stuff if needed. I understand the basics of layers and how to use them. But, I really lack the ability to imagine something beyond the image and be able to take it there in post. Messing around with these helps me get a little bit stronger with that part of my photography.
Note, I believe post-work should be there to help you create something you see in your mind's eye. If you are actively capturing the image with your camera and you notice something you want to fix, and you tell yourself "I'll just take care of that in post." -- smack yourself. I think that advice comes from Zack Arias, and I feel its worth repeating.