Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
Google Drive to Slack - Slack notifications whenever you work on Google Drive docs
TechEvents.co - Tech and startup events aggregator
Kissflow - Kissflow is a workflow tool & business process workflow management software to automate your workflow process. Rated #1 cloud workflow software in Google Apps Marketplace.
Facebook Local - Discover places to go and events happening near you
Heymarket for Slack - Text and Facebook messaging from Slack