LeechBlock NG (Next Generation) is a simple free productivity tool designed to block those time-wasting sites that can suck the life out of your working day. (You know: the ones that rhyme with 'Blue Cube', 'Space Hook', 'Sticky Media', 'Quitter', and the like.) All you need to do is specify which sites to block and when to block them. You can specify up to 30 sets of sites to block, with different times and days for each set. You can block sites within fixed time periods (e.g., between 9am and 5pm), after a time limit (e.g., allow up to 10 minutes in every hour), or with a combination of time periods and time limit (e.g., allow up to 10 minutes in every hour between 9am and 5pm). Additional features include:

Lockdown: Block sites immediately for a specified duration.
Access control: Set a password or random access code for the options page, to slow you down in moments of weakness!
Delaying: Set a countdown to delay access to sites instead of completely blocking them.
Password: Require a password to allow access to blocked sites.
Wildcards: Block a range of sites (e.g., *.somesite.com).
Exceptions: Whitelist sites you don't want to be blocked (e.g., +allowedsite.com).
Keywords: Block or allow pages based on keywords (e.g., ~badword).

Version history: https://www.proginosko.com/leechblock/version-history/ Documentation: https://www.proginosko.com/leechblock/documentation/ Usage examples: https://www.proginosko.com/leechblock/examples/ Permissions: https://www.proginosko.com/leechblock/faq/permissions/ Frequently asked questions: https://www.proginosko.com/leechblock/faq/ Support: https://www.proginosko.com/leechblock/support/