You have a structural problem with your database. Many people need to link to many events--what we call a many to many relationship. While a return separated list of values can be used for this, it's not nearly as flexible as using a join table instead:
Events::eventID = Event_People::EventID
People::PeopleID = Event_People::PeopleID
And note that I didn't use the name of the event in these relationships. Consider what complications ensue if you have to change the name of an event after creating records that are related by that event title...
To answer your specific question, you can use the list function to pull up a return separated list of dates from the events table. List ( Events::EventDate )
Here's a demo file that coincidentally uses events and contacts in a many to many relationship that you may find useful to look over for ideas on how to set up a join table for your database: http://www.4shared.com/file/dZ0bjclw/ManyToManywDemoWExtras.html