Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
Abend - Every party starts with friends. The better FB events app.
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
WebRezPro - WebRezPro offers property management system [PMS] for properties of all types and sizes.
Bigtent - BigTent is a web-based organization and communication portal for groups.
Cloudbeds - Cloudbeds is the platform that powers hospitality, enabling tens of thousands of lodging businesses in more than 150 countries worldwide to grow and thrive.