GPS work indoors!

As of just yesterday, the GPS works indoors! I was in my basement and went into google maps and pressed the location button. After the pulsing circle it went down to the pulsing blue dot that I only saw when I was outdoors. It placed me in my backyard about 30 yards from actual location. Same thing happened today, went out after work, was in a bar (indoors) and the same thing, location pinpointed my position with the pulsing blue dot. I was quite impressed. Anyone else seen this? Doesn't always work inside but sometimes it does.