Earth Hour doesn't mean you can't use electricity at all, only that whatever you do during that hour (work, watch tv, listen to music, play PS) you should do it with your lights out, of course I read their
FAQs after spending one hour in the dark, completely unplugged and bored to death (should have started there before going on full-hug-a-tree mode). But it's a lot easier to do and the effect is relevant. In fact, it's so easy you can do it every day of the year.