I block it using my hosts file and unblock it (and HN) about once a week. Then I look at the top content from that period of time and look at it all at once, then bookmark them (in a folder) and usually never click the bookmark again.

Facebook I'll check about once a month (also blocked in hosts).

I got into the habit of instinctively typing in "news." or "redd" into my browser as soon as I sat down, the lost productivity was too much and the hosts solution seems to work for me.

For PC games, I have to uninstall them. I'm actually glad games are 60 GB these days because it means I have at least 1 day to consider playing a game. If at any time I decide I don't want to waste 50 - 100 hours playing I can cancel the download and delete the files. Yes, I'm getting Google Fiber next year and this method will not be available because it will download in about 10 - 20 minutes. I'm looking into a time-delayed safe or the cheap plastic tubs with a timer for storing an SSD for those games.