Konflist - Curated list of tech conferences all around the world!
Event Hunt - Startups and Tech Events Curated By Locals
Leade.rs - Leaders matches event organizers with speakers in tech.
TechEvents.co - Tech and startup events aggregator
Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
Shapr - A completely free way to build your professional network.