Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
Goodreads - See what your friends are reading.
Facebook Local - Discover places to go and events happening near you
LibraryThing - A home for your books.
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
GoodBooks.io - Largest curated collection of 8,500+ book recommendations.