WARNING: There is one "holy s**t" at the end of the video, so turn the sound down if you don't want to broadcast that.
This is a video of what I consider to be the most impressive fire "art" at Burning Man 2006. It's a performance called 2BLEVE that featured two tanks of gasoline, kerosene and lamp oil pressurized with propane set off at the same time to create two fireballs that merged into one fireball. The two tanks were 90 feet apart to give you an idea of the scale of the thing.