Comment by noir_lord

I put

    #127.0.0.1      www.reddit.com reddit.com i.reddit.com slashdot.org www.slashdot.org www.theguardian.com theguardian.com
    #127.0.0.1      www.facebook.com facebook.com
    #127.0.0.1      news.ycombinator.com

In /etc/hosts when I'm supposed to be working that way when I hit any of those it bounces me back to my current project and I think "oh yeah, supposed to be working".

Crude but effective.