My network admin apparently has Windows updates setup to auto-install and reboot if needed so the computer had done that last night and Visual Studio 2012 was reloading upon startup when I came in this morning.
To my surprise. I was greeted by a series of errors popping up as Visual Studio 2012 fired up, concerning the loading of packages.
In my case it was a number of different packages, one of them being PasteJson.JsonPackage. Restarting VS 2012 didn't help.
The issue turned out to be that VS 2012 maintains some sort of cache (meta data most likely) about the packages and it was either outdated or corrupt for some reason.
You can fix this situation easily by going to C:\Users\[INSERT USER NAME HERE]\AppData\Local\Microsoft\VisualStudio\12.0\ComponentModelCache and deleting all files you find in that folder.
No more errors after that. :-)
Someone mentioned to me that this might be a recurring issue so until it's fixed, just delete the files again.