Earthquake

We had a bit of an Earthquake last night; 5.6 on the Richter scale.  We were getting ready for bed about 10:55 pm and heard, what we thought, was a low-flying airplane.  But the sound and then shaking, picked up and it seemed to take forever for it to stop.  The authorities say this was the most powerful quake in Oklahoma recorded history & we have earthquakes all the time, over 100 for 2010.  But this is our first experience.  All I can say is "Weird"!!!