Envoy - Visitor registration that's changing how guests are greeted in companies around the world.
Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
Teem - Cloud-based meeting room booking system
Event Hunt - Startups and Tech Events Curated By Locals
RobinPowered - Robin coordinates meeting spaces, people, and things in your office. Complete with analytics and insights that uncover usage and help optimize space.
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets