In winter 2014, the USPSOIG was contacted by the 18F division of the GSA, inviting us to be among the first .gov domains to be hard-coded into the HSTS Preload List, as part of a kick-off initiative to get other agencies to follow suit. We agreed, and I was tapped to do the actual implementation. Ultimately, it wasn't very complex, but the testing involved was extensive, since we had to ensure that all of our subdomains (including internal resources) were ready. And I particularly enjoyed working with 18F; they're a great agency doing excellent work!