Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
TechEvents.co - Tech and startup events aggregator
Event Hunt - Startups and Tech Events Curated By Locals
Attendize Event Ticketing - Attendize is a free & open-source ticket selling and event management platform
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
All Design Conferences - A list of all front-end and design conferences