Small Earthquake Felt in Northern Virginia

I just experienced my first earthquake, getting shaken awake at about 5:02am. Not sure how long it lasted, but after waking up, it felt like my bedroom was inside a giant cell phone on the vibrate setting for about 15 seconds. Did you feel it? Let us know in comments. UPDATE 5:15am: US Geological Survey reporting a preliminary magnitude of 3.7, centered near Gaithersburg, MD. UPDATE 5:26am: After being reviewed by seismologist, USGS puts quake at 3.6 centered a bit closer to Germantown, MD. UPDATE by Lowell 5:41 am: Great work by Miles, who posted this news 7 minutes before the Washington Post. So far, no word from the Sun Gazette, the Connection Newspapers, the Washington Times or the Washington Examiner on this story. UPDATE 6:06am: Not Larry Sabato says it looks like a lot of people got woken up by the quake & just decided to stay up, tweeting, "Hysterical- the #DCQuake really woke a lot of people up. Traffic already tied up for morning commute in #Rosslyn outside my window." UPDATE 6:10am: From NBC's Jeff Rossen via Twitter: "USGS: The quake was largest recorded within 50 kilometers of Washington DC since a database was created to track activity in 1974."