Don't let your guests forget about the event! Schedule email reminders from within your event settings to alert guests before their scheduled time. To set up an email reminder edit your event from the Manage Events admin page. "Upcoming Event Email Reminder" is found under the Reports and Emails section (just above "Advanced Options").
Multiple times can be scheduled in hours or minutes before the event, so you can stage a series of reminders. Or keep it simple with one timely alert sent an hour or 30 minutes before their event starts.