Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
WhosDown - App where you can genuinely make friends—connecting with someone that shares a common interest
Facebook Local - Discover places to go and events happening near you
Meetup for iOS and Android - Discover groups that are all about the things you love
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
MEETplnr - Organize meetups in your chat groups with ease