A Campaign is the easiest way to raise money online and you can easily create your own fundraising campaign for over 1.5 million charities.
An Event is a collection of fundraising teams. Create an Event for one cause or a bunch of causes.
Examples of events are the TCS New York City Marathon and the UTA Big Bowl event. If you're the Event organizer (that means you're in charge of putting on the entire event), you'll want to create an event page where individuals and teams can come and join your event.