Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
Airfordable - Payment plans for flights before your departure.
Event Hunt - Startups and Tech Events Curated By Locals
Sygic Travel Maps - Itinerary planner for independent travelers
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
Stride Travel - Search and reviews for tours & adventure packages