I participated in the SANS Holiday Challenge this year and really enjoyed it.  I didn't end up winning but I am proud of the honorable mention I received on the SANS website.  The concept of this years challenge was built around the Miser brothers and the goal was to hack each of their industrial weather control systems.  You can read my full write-up here: SANS Holiday Challenge 2012 Write-up

 

The original SANS Challenge posting can be found here: http://pen-testing.sans.org/holiday-challenge/2012

 

The winners/answers to the challenge are posted here: http://pen-testing.sans.org/blog/2013/01/18/holiday-challenge-2012-winners-and-answers