NASA has been doing extensive testing of its new 5M15 rocket out in the Mojave Desert, and by the look of things, it's awesome. The engine runs off compressed liquid methane, which NASA believes to be a smart choice.
The odorless substance has multiple advantages over conventional rocket propellants: It's cheaper, it requires much less insulation, and it exists on several planets NASA hopes to travel to, like Mars.
After watching the video I think it's safe to say that it's perfectly normal if it makes you hot and bothered. I had a pup tent appear as soon as the engine fired up, and I'm going to display it proudly all day as my way of saying "I love rockets".
The video after a jump (make sure to have the sound up for full effect).
NASA's New Rocket [wired]