Airfordable - Payment plans for flights before your departure.
Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
Vamo - Build your own adventure
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