cyberstorm II is a massive computer security "exercise" to take place the second week of march.The seeming coincidence of exercises "going live" can't be ignored... http://www.infowars.com/?p=552 I think seizing complete control and denying use of the net would be a first step in any paranoid(?) agenda.
The simplest thing to do would be - assuming I were a malevolent government agent - to wait for, and not prevent, a terrorist attack disabling key Internet corticals, which would shut down the Net in wide areas, and then 'fail' to restore service for some reason. Or engineer such an attack. No, of course, that anybody would do that.