Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
Booking.com - Find your next stay. Search deals on hotels, homes, and much more...
Event Hunt - Startups and Tech Events Curated By Locals
Tripadvisor - The Tripadvisor mobile app is available for the Android and iOS platforms. It can be used to create reviews of hotels, restaurants, and to chat with other travelers on Tripadvisor forums.
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
Sygic Travel Maps - Itinerary planner for independent travelers