Was doing a little searching, and found a quick way to get some .gov backlinks using forums (this is an offshoot of from the .edu backlinks post below this one). I did a google search for the following phrase: 'inurl:gov/forum/*register' (remove ' ') and it gave me several thousand links to many .gov domains where you can register as a user. Tried one-it got indexed within a couple of hours, and it shows up on one of my blog inlinks. Crazy. Enjoy!