Hi, welcome to GovtGit.com. This is a hobby site for me to have an excuse to play around with a few things I found floating around the internet. First is an API that lists verified social media accounts that belong to the US Government. There's more than just GitHub, but that's the one I wanted to play around with. It also gave me an excuse to play around with the GitHub API.
Also came across a PHP routing library called AltoRouter that makes routing pretty easy. Saved all sorts of time getting this up and running.
Okay, enough of the why. Below is a list of all the government agencies that have GitHub accounts. Click on the name of one you're interested and it will bring up a list of individual GitHub accounts within that agency and any projects.