Attendify - Develop relationships at the events that you attend by creating smaller events with just a few people.
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
Cvent - Cvent's event management software provides event planners with a complete solution to increase event attendance and decrease event costs.
EventMobi - EventMobi is an interactive mobile event app, audience response and engagement platform for conferences and trade shows.
Eventzilla - Eventzilla lets you sell tickets online and manage attendees from one integrated application.
Socio - Connecting with people is just a "phone shake" away!