Airbnb - Book unique places to stay and things to do.
Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
Sporteventus for iOS - The worldwide search engine for sporting events and tickets
Event Hunt - Startups and Tech Events Curated By Locals
Up All Night - Concerts and exclusive events for $25 a month
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets