Guides by Lonely Planet - Explore city guides curated by experts.
tripcake - Doodle for travel plans with friends
Foursquare City Guide - Foursquare City Guide is a Free to use mobile application that will lead you to the perfect spot anytime anywhere around the world.
DUNK - Surprise your friends with secret group plans
Lonely Planet - travel guide book publisher
Howbout - Social calendar app to easily make plans & find availability