Yellowstone National Park is one Super Volcano that comes too mind.
One in Indonesia as well Lake Toba.
If one of these babies goes off we will all know about it.
I follow this site for Earthquakes
http://earthquake.usgs.gov/earthquakes/recenteqsww/
And this one for Volcanic activity
http://www.volcanolive.com/news.html
Cheers,
Duncan
