There were some seriously awesome/creepy clouds over the town of Joplin, Missouri. Stuff straight out of Ghostbusters!
Check out these two:
Just look back and forth between them. They were obviously taken just a few seconds apart. Imagine sitting there, able to SEE that air is actually a fluid!
Of course, also imagine sitting there, knowing that the sky looked like it did because of the sort of air currents that lead to tornado formation.
You can see even more pics here:
One of those is my new desktop.