A very simple way to get data from the meetup api and convert to CSV format.
All you have to do is 1) get a api key from meetup (https://secure.meetup.com/meetup_api/key/) and modify the https://github.com/GDG-NewYork/meetup-api-python/blob/master/getmetrics.sh file. 2) if you would like to change the meetup groups that are queried, you can modify https://github.com/GDG-NewYork/meetup-api-python/blob/master/runall.sh.
Optionally, you can load into Google BigQuery and use a visualization tools such as redash.io (requires a Google Account and a BigQuery project). For examples of this, see https://bigquery.cloud.google.com/table/personal-real-estate:gdg.meetup and http://demo.redash.io/queries/156/source#199 (requires Google Account and BigQuery project)