I think a thread like this would be a lot more successful if people just photoshopped a single image in their own way (i.e. OP posts a picture, everyone posts their own take on it, and a new source image is selected when everyone becomes bored with the original one).
The way it is now, you have to rely on the previous poster actually having done something funny that you can add on to.
Also, using content-aware fill/healing brush on everything is nearly as bad as pointillizing the whole image.