Here are three, all good news, more possible:

1.  QE3, all hail Scott Sumner.  The ECB’s unconventional easings to banks and sovereigns deserve mention as well.  Perhaps someone will make a lot of money betting on high average inflation in the OECD, I doubt it. 
I suspect that gerontocratic deflation will be a strong temptation for OECD central banks over the next few decades, glad they’ve resisted that urge so far.  
2. Taking Shale for Granted. The Bakken formation’s massive shale deposits were literally the stuff of urban legends a few years ago. This year, according to a Reuters survey of energy analysts and others, financial professionals are about evenly divided on whether or not shale is a big deal.  Debates about the economic power of North Dakota have shifted from tinfoil hats to pajamas to pinstriped suits (PDF) in just a few years.  
The future of shale is uncertain but it’s reasonable to believe the supply curve for carbon-based energy is fairly flat.  
3.  Driverless Cars Becoming Legal. So far: CA, FL, NV.  In April I tweeted:
A thin edge of the wedge for Google Cars: an alternative to driver’s licenses for some of the elderly. Voter demand meets tech solution.

Nobody wants to take away Grandma’s car keys, partly because nobody wants to drive Grandma everywhere.  In October, Google CEO Sergey Brin said this at a press conference with California Governor Jerry Brown, after noting that driverless cars would be a boon to blind individuals: 

Some people have other disabilities, some people are too young, some people are too old…
I hope that 2013 offers many more good economic news stories.