Mac OS X Mountain Lion has 43 secret desktop wallpapers hidden in one of its folders. They are all beautiful, high quality and this is how you find them.
If you'r a fast typer and don't pay much attention to spelling or English isn't your first language? No biggie, you can get a spell checker add-on for Firefox.
Pretty simple and useful tutorial, where you will open a random photograph with smoke and convert it into something really not friendly for our environment.