It looks like a statistical anomaly as others have suggested. I'm in the btcguild pool, and we found 8 blocks in a one hour period earlier (according to btcguild our luck in the past 24 hours is +27.3%) but our pool is still at only a bit over 2 t/hashes. I expect to see that number on bitcoincharts.com drop significantly tomorrow unless the lucky streak continues. I really doubt 5 new thashes/s of processing power came online at just about the same time we had our crazy lucky streak