ClickMeeting - Collaborate with partners and clients using ClickMeeting professional web conferencing software. Try it now, FREE!
Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
Zoho Cliq - Team chat that's built for work
Event Hunt - Startups and Tech Events Curated By Locals
GoToWebinar - Webinar & Online Conference | GoToWebinar
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets