TechEvents.co - Tech and startup events aggregator
Eventil - Product Hunt for tech events
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
Facebook Local - Discover places to go and events happening near you
Konflist - Curated list of tech conferences all around the world!
Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.