Important emails have a habit of arriving at inconvenient times. Boomerang is a plugin for Gmail, Outlook and Android that lets you temporarily dismiss messages from your inbox, to reappear in a few hours or days when you're better able to deal with them. You can also pause your inbox entirely, to suspend the torrent of interruptions while you're busy, and schedule outgoing messages to be sent at specified times. You get 10 free uses a month; after that, monthly subscriptions start at $5. The idea couldn't be simpler: you set up a list of possible dates and times and then your invitees drop by the Doodle website and tick the options that work for them. You'll quickly be able to see at a glance when everyone is available and since recipients don't need to create their own Doodle accounts, it's friction-free.