Brian Wendt

Meetup Venues allows you to list Meetup.com events associated to a venue. This plugin is useful for the venue’s 
website to display what is going on at their venue.
A caveat to this plugin; when groups/users post events they do not always use the existing venue. This results in there 
being more than one venue listed per real physical location. You may need to use a comma deliminated list for the 
venue_id attribute.

Meetup.com Venues

This plugin allows you to list Meetup.com events associated to a venue.

Rick Radko

A simple widget for use with a <a href="http://meetup.com" rel="nofollow ugc">Meetup.com</a> group. The plugin adds a widget that shows a link to your Meetup group.
Simply enter your Meetup group name and it’s URL and save. You can display the widget with or without a title.
Support
Support for this plugin is limited to fixing confirmed bugs and improving the plugin with enhancements that can be reasonably accommodated.

R3DF Meetup Widget

A simple widget for displaying a link to a meetup.com group.

Meetup.com Venues vs R3DF Meetup Widget