The new version of the indispensable Photoshop image editor came out a couple days ago, and includes an unbelievable feature called Content Aware Fill. According to Adobe:
We have developed interactive image editing tools using a new randomized algorithm for quickly finding approximate nearest neighbor matches between image patches.
Essentially it removes unwanted items from an image instantly and seamlessly. Alterations that used to take a skilled Photoshop user hours to preform are completed in seconds with almost no competence required. Watch these videos; and if image editing is a time consuming part of your work, prepare to pick your jaw up off the floor.
This one starts off with minor tweaks, like removing lens flare and bits of trash from a scene, but skip to the middle or so to see the ridiculously awesome stuff.
This video shows how great this is for easily toughing up images.
There is a better explanation of how Content Aware Fill works, here. I prefer to think it uses witchcraft or is the rudimentary self-aware beginnings of Skynet. Run for it, Sarah Connor.