Topic moved here from the issue tracker:
Intent seems to do this in a more gentle and helpful way (and on a per-site basis), as opposed to StayFocusd’s all-out blocking of all distracting sites once the time is out:
LeechBlock is another pretty decent one (it can “delay” pages).
For linux users
/etc/hosts might be a good solution.
Although that would be very hairy from a security stand point with having an extra user for activity-watch being the best solution i can come up with.