What is the longest time gap between blocks in 2010 - 2011?
I wrote a program that extracts the blockchain into an SQL database and ran a query. The answer is that block 152218 followed block 152217 after a delay of 1 hour 39 minutes 7 seconds. This was the longest inter-block interval in 2011. There were many longer interval in the early history of the blockchain, often multiple hours or days.

Edit: I also find it interesting that there have been 78 blocks where the inter-arrival time was less than one second.