I find that if I’m not “in the zone” when it comes to getting a task done, I can be easily distracted by reading the Ars Technica or Something Awful forums, my aggregator, TV whatever.
So I’ve gotten into the habit of doing a few things when I really need to focus.
Plus I can never really get into stuff until its after 10PM or so, I just can’t focus when everyone else is awake or something :)