This is: (a) unimpressive, because it's obvious that you went and registered a bunch of domains with a version of their name that they don't use (christopher, benjamin, melvin, middle initial, etc), and (b) a bad idea, because at best it's lulz for geeks in the know, but at worst it's "SOPA opponents have gone too far: they hacked web sites of the U.S. government!" Lose it.
ftr, I didn't do it. But I do think it's smirk-worthy. To each his own.