On Wednesday, Yellowstone National Park launched a new webcam service that lets you spy on Old Faithful and the park's other huge geysers. The webcam gives live, streaming images 24 hours a day (though I must admit that watching during the night hours isn't so exciting).
Even in the daytime, you might have to watch for awhile before any action happens. Old Faithful erupts every 90 minutes or so, when the expansion of steam bubbles inside exerts enough pressure to explode from the ground—shooting hot, hot water more than 100 feet into the air.
The park has other webcams, too. One shows the New Mammoth Hot Springs; another shows the air quality at the parking lot of the Old Faithful Inn. Or, if you don't care much about the video, but want real-time information about Yellowstone's volcanic activity, head over to the Yellowstone Volcano Observatory.
(Flickr, by glennwilliamspdx)