A flexible solution may work with CCK, FeedAPI and creating a custom PlingsInput module for making the input API calls.
This would involve:
1) Creating a CCK content type which mirrors the fields in the Plings Output API/Input API. This can take advantage of all the existing CCK fields such as NodeReference (for maintaining the relationships between events, venues and host organisations), link, images, location etc.
Where particular validation for Plings Input API fields is required - this could involve creation of an additional CCK field type, or validation routine.
The creation of an activity record could take advantage of Youth Agora's 'complete' module for showing how complete a record is.
It also gives maximum flexibility for CCK activities to be represented in Views. CCK is moving into Core in Drupal 7.
2) Creating a FeedAPI Parser that parses Plings Output API RSS and XML (depending on presence of API key) into the CCK nodes set up in part (1).
This would allow a Drupal install to pull in Plings data and display it in all sorts of ways through Views, Faceted browsing etc.
Anything that can be done with a node could be done with a Pling.
(3) A custom module would need to be written that calls the Plings Input API when a 'Plings' activity type CCK node (or 'Venue' and 'Provider') nodes are edited.
