Yes, Photo-Brush is a lot of fun.
There are many special effects you can apply, you can paint with Image Nozzle, you can even use cloning from texture or original etc....
Here are few more samples if you don't have enough...
Have fun with the Image Nozzle.
Spray various plants, lego blocks, coins... and spice up your images
Add realistic Lens Flare to your images.
Make cartoon faces of your friends with Warp Tool.
See unseen details with Termo-vision filter.
Age the Photo, back in 1920
Apply any of the many build-in effects like Page Curl, Mosaic Solarize, Quantize, Glowing Edges and many more. See some example.(Applied Aged Photo, Glowing Edges and Page Curl)
Create interesting image-in-image effect using the Fractal-Droste.
Build your own Little Planets from an ordinary photo (it doesn't even have to be panorama)
Create cool text effects with rendered drop shadow and 3D.
