I was browsing the internet and I recently stumbled upon a neat little program called Project Dogwaffle. Project Dogwaffle (PD for short) is a very powerful (and free!) "painting" program. This program allows you to paint without the mess and the fumes of regular painting.
Project Dogwaffle has an amazing way of painting by using optipustics. Under the optipustics settings window you can set properties of your paintbrush to achieve effects of moss, grass, explosions, etc. or you can turn optipustics off and just paint with a regular brush.
The picture included on the right was painted using Project Dogwaffle's optipustics functions. With it we were able to create a very nice explosion, something that would have taken much longer to create using traditional methods in Photoshop.
An incredibly handy feature of Project Dogwaffle is that you can export the graphics to edit them in another program (Photoshop for example).