Water Explodes in Microwave

I was boiling some water in the microwave to add to some instant oatmeal. 
I put about 3/4 of a cup of water into a 1 cup glass measuring cup for 3 minutes and left the room.

When I came back I thought I would give it a quick reheat and wait until I saw the boiling bubbles to make sure it was at boiling.
I put it on for one minute and watched for the bubbles.
All of a sudden "POW"  the water exploded right out of the cup all over the microwave.  When I opened the door the cup was intact but there was only 1/4 cup of water in it.

Immediately I googled "water explodes in microwave."

Here are some of the sites with the explanation.  I guess I'm lucky that it didn't blow up in my face.  Guess I better get some wooden stir sticks since I always boil water in the microwave. 
In case you don't read the articles, putting some non-metallic object in the water to help diffuse the built up energy that causes the explosion.

There were two things I did differently this time than usual.
1.  It was the first time I used a one cup measuring cup
2. and the first time I boiled so little water and then tried to reboil it

http://www.stevespanglerscience.com/experiment/exploding-water-in-the-microwave

http://www.snopes.com/science/microwave.asp