Funny... our weather forecast didn't call for an earthquake tonight...
At 8:40, we had a series of sudden side to side jolts, which could be nothing other than an earthquake. Here in the Bay Area, we're used to these things, and it didn't last very long at all.
Like other recent earthquakes, the epicenter appears to have been on the Hayward Fault in the East Bay. Despite the frequency of temblors, the Bay Area has been relatively incident-free for the better part of twenty years.
Early reports have the earthquake at 4.2., stronger than the 3.4s and 3.5s of recent history, but not alarming.
Previous quake-related posts:
12/22/06: A 3.7 Earthquake? Call Me When You Hit 5.0.
6/15/06: Earthquake Shakes Things Up