EventsBase - Find the best professional events nearby or globally
Slack News Feed - Get the top posts from every Slack chat you're in.
Rally by Eventbrite - Find the best local events and rally your friends to join
Slinky - Your slack links — organized!
Calendall - Follow the best events online, without leaving your couch.
Tettra - Tettra is a company wiki that helps teams manage and share organizational knowledge.