A sample push API consumer for the new foursquare push API.

Has a very simple endpoint for doing OAuth, and a /checkin handler that
receives a POST with checkin and user JSON. The POST is expected to have a
"checkin" parameter containing a JSON checkin object,  with "user" and
"venue" json inside it. Those formats are described in more depth at
http://developer.foursquare.com/docs/responses/checkin.html.