The 5:33am earthquake woke me up. It also scared me for a moment. I live on the 12th of 23 stories in a concrete building. This was the first time that I had been in my place for an earthquake. The feeling of the 4.0 quake was more elastic than those that I have felt before. I suspect that this is because I was 12 stories offof the ground. I have been on the 2nd story of concrete buildings before and the feeling I remember was a quick, solid jolt. I am not sure if the difference lies more in the nature of the rubbing of the faults or the difference in height. I'm looking forward to continuing this research with the next earthquake.
For the time-being, check out this video of skyscrapers swaying in Japan during their big earthquake.