Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.

Travel Diaries - Create your own travel diary to capture your experiences

TechEvents.co - Tech and startup events aggregator

Magpie - Female travelers club - meet women like you when you travel

Facebook Local - Discover places to go and events happening near you

tripcake - Doodle for travel plans with friends