Fogus/fog helps you focus by creating a "fog" around websites you don't want to visit. It's a beautifully designed and insanely user friendly website blocker. You can set the time when you want certain sites to be blocked. For example you can set that certain sites, e.g. "evil.com", will be blocked during working days from 9-5. But will be available in the evening and in the weekends. Not only can you block certain websites, but also whole classes of domains, e.g. by typing in "xxx". So, every domain containing "xxx" will be blocked.