In the recent year several big earthquakes have made the news.
Most of these quakes happened in the Pacific Ring (Ring of Fire) and seem to proceed in a clockwise manner.
Below is a little map, which brings up the question if an earthquake is now due next for California or Mexico, in order to complete the circle.
It is well known that a big earthquake is being expected for California. It is also known that earthquakes beget earthquakes, because shocks in one area can put things in motion elsewhere in a connected system.

The first big quake was in Haiti, 12 January 2010. The damage was enormous.
46 days later an even bigger quake happened in Chile (27 Feb 2010).
189 days later a 7.1 earthquake struck in New Zealand (4 Sep 2010).
And now 188 days later there is the disaster near Sendai, Japan (11 March 2011).
Some people will say that the recent earthquake in Christchurch (22 Feb 2011) killed more people, but this was considered an aftershock of the Sep 4 quake. This afterhock came 171 days after the original quake in the same area.
Now, the first thing we can observe here is that all these time intervals are very close to multiples of 9.
46 ~ 5 * 9
189 = 21 * 9
188 ~ 21 * 9
171 = 19 * 9
So these 5 earthquakes have come on a 9 day rhythm.
I also noted how Christchurch and Sendai are almost equal distance from Haiti. Measuring with Google Earth I found 11060 km and 10720 km respectively. And the earthquake in Chile happened about 5700 km away, close to half that distance. If another earthquake next happens near California , it would also be ~5500 km away from Haiti.
Next I measured the vertical distances connecting South to North. From Christchurch to Sendai is 8720 km (8700 between the epicenters). Going from the place of the quake in Chile up North along the Pacific Coast one comes right to San Francisco after 8720 km. Same distance.
If a next quake happens there after 189 days, then it would come on 16 September 2011, give or take a day. This will also be the week that marks the 10th anniversary of the Sep 11 2001 attacks.
Personally I suppose all this will be too perfect to work out in practice. Patterns of great symmetry only work till they disappear again.
But anyway, if a major earthquake happens in that area around that time, then you read about it here first ;-)