Department of Focus by Lachlan

Department of Focus helps you stay on task by blocking distracting websites during the hours you choose — with enough friction that changing your mind takes a deliberate effort, not a single click.

Features:
• Blocking groups — Organize sites into groups (social, video, news, your own list). Turn groups on or off from the toolbar popup.
• Schedules — Set days and time windows when each group is enforced (for example weekdays 9:00–17:00). Schedules can span midnight.
• Hourly allowances — During blocked hours, optionally allow a few minutes of browsing per hour before sites lock again until the next hour.
• New-tab limits — Optional rules for opening too many new tabs during a lock period.
• Challenge lock — Editing settings or disabling protection requires answering a short set of math and trivia questions. After you pass, you have a few minutes to make changes before the lock return