Okay, it's the end of the world, and you heard it here first

US News & World Report has a series of blog posts by James Pethokoukis about the caldera at Yellowstone:

There have been eighty volcanic eruptions at Yellowstone since the last "supervolcano" eruption 640,000 years ago, and hundreds of large steam explosions, some near the Lake. The last time a volcanic eruption occurred at Yellowstone was 70,000 years ago.

Yellowstone seismicity increased significantly in December of 2008, due to an energetic earthquake swarm that commenced on 26 December. This swarm, a sequence of earthquakes clustered in space and time, is occurring beneath the northern part of Yellowstone Lake in Yellowstone National Park. As of this writing, the largest of these earthquakes was a magnitude 3.9 at 10:15 pm on 27 December. Through 5:00 pm on 31 December, the sequence had included 12 events of magnitude 3.0 to 3.9 and approximately 20 of magnitude 2.5 to 2.9, with a total of at least 400 events large enough to be located (magnitude ~1 or larger). National Park Service employees and visitors have reported feeling the largest of these earthquakes in the area around Yellowstone Lake and at Old Faithful and Grant Village.

Tthe number of magnitude 2.5 or higher quakes in the Yellowstone area for the entire decade of the 1980s was 128.
The number of magnitude 2.5 or higher quakes for the region directly around the lake in the last four days was 30.

Rico says if it ever blows (and it will, eventually), we're all screwed... (This may be a case where being proactive, as in drilling into the mantle to relieve the pressure, even if it forms a volcano, will be better than waiting for it to explode. Remember, you heard it here first...)