Gav and Dan over at the Slow Mo Guys are famous for creating bizarre events in front of powerful HD slow motion cameras. This spinning tornado of fire is especially great. Although this particular flamey vortex was created artificially using box fans, you can sometimes see real fire tornadoes in the middle of forest fires or spinning off from the plumes near an active volcano.
Nature by Numbers
A beautiful movie that depicts the fascinating connection between numbers, geometry, and nature by Cristóbal Vila.