Detour - Immersive audio walks, now in 17 cities
Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
Sygic Travel Maps - Itinerary planner for independent travelers
TechEvents.co - Tech and startup events aggregator
Foursquare 10 - Your ultimate city guide, in your pocket
Facebook Local - Discover places to go and events happening near you