This set blocks five time-wasting sites between the hours of 9-11:30 a.m. and 1-4 p.m. on the weekdays.

I have a bit of a problem. I obsessively check certain websites (cough, cough, Facebook) when I’m supposed to be working. Is there a way to block those sites during the workdays but still allow access after hours and on the weekends?

Firefox makes this easy to accomplish thanks to its ultrahandy add-ons, specifically one called LeechBlock. Go to Tools > Add-ons > Get Add-ons, and type LeechBlock into the search box. Once it’s installed, go to Tools > LeechBlock > Options, and you’ll find a huge list of options for blocking those time-wasting sites. You can specify certain days and times, what page Firefox displays instead of the blocked one, and lots more.

To block a site in Safari without using Tiger’s or Leopard’s Parental Controls (which you can’t use on an administrator account anyway) or fiddling with the Terminal, you can install the free add-on Safari AdBlock (safariadblock.sourceforge.net), and make it think your time-wasting sites are just giant ads. Go to Safari > Preferences > AdBlock, click the Custom Filters tab, click the plus sign, and set the pull-down menus to Block Elements Whose URL Starts With http://your-blocked-site.com. You can turn AdBlock on and off in that same preference, under the General tab, for times you want to allow yourself to squander a few minutes online. (Now get back to work.)