(inspired by http://blog.doughellmann.com/2012/12/new-years-python-meme.html who credits http://blog.ziade.org/2012/12/23/new-years-python-meme-2012/ )
ipython-notebook. Of course, it's the second or third time I've "discovered" it, but it's gotten very sophisticated.
Pushed some limits for mock testing on Unix - a python script that creates Subversion and Git repositories and substitutes calls to sendmail, for example. Also spent a lot of quality time with boto...
A couple of patches to kivy and pypi-install - I've been doing a lot more bespoke automation and release engineering that are at the top of a tall pyramid of open source that actually works, so there have been fewer things for me to dive in and debug...
Reddit r/python and Python Planet - and anything that comes by on twitter; I'm not a hugely faithful blog reader this decade, but twitter is a great circulator of ideas...
What are the three top things you want to learn in 2013?
ipython-notebook
more robotics - with an emphasis on actually controlling hardware.
What are the top software, app, or lib you wish someone would write in 2013?
A low-overhead mobile (Android, but Firefox OS would be tempting too...) native python app development environment.