"logan" is a Ruby gem constructed to interact with the Basecamp API. Currently on version 0.1.1 at the time of this submission, the gem appears to be well supported and documented, compatible with the new Basecamp API. Though not officially built by Basecamp's provider, 37Signals, "logan" is fully endorsed by Basecamp on their GitHub channel and developer site.
Dropbox has launched the DBX Platform, a suite of APIs and developer tools for building new capabilities on top of Dropbox. The company has also launched two new APIs; Metadata API and File Requests API. Both APIs are built on Dropbox API V2, the revamped API that replaces Dropbox API V1.