Meetup hosts an extensive selection of feeds readily available for syndication. Some feeds don't require an API key to access the info, and are available in either RSS, Google, Outlook, or iCal calendar formats.
For some types of applications, consuming raw syndicated feeds is the simplest path to Meetup integration.
You can get a feed of the upcoming events for a group in iCal format with
Replacing group_urlname with the urlname of the target group.
Calendars belonging to groups with private content are restricted to member-only access. If you are a member of a private group, you may access your group's calendar by appending your API key to the url
You can also subscribe to a Meetup Group's event and rsvp feeds from the Group's homepage under the Calendar tab.
You can find a link to your member-specific feed of Meetup events you are attending. To get this link, just login to Meetup.com and click on the "Export to…" link below the calendar on the Meetup homepage.