Status.im - A Mobile Ethereum OS
Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
Signal - Fast, simple & secure messaging. Privacy that fits in your pocket.
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
LinkedIn Events - A new way of connecting people from LinkedIn
Meetabit - All the local tech and startup meetups in one place - easy to organize & attend