Find A Maker - find a partner for your next project
Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
CoFoundersLab - Meet 250,000+ entrepreneurs online
Facebook Local - Discover places to go and events happening near you
Founders Nation - Find or become a startup cofounder
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets