PHP Interface for Sending Data to Google Analytics via the Measurement Protocol.
This is very useful for scenarios where the data you want to submit does not naturally occur in a client-side/browser/js context, and/or where the most straightforward place to capture data (events, user dimensions, etc.) is in PHP code.
Simple example usage:
$gamp = new GAMP();
$gamp->sendEvent('My Event Category', 'My Event Action', 'My Event Label');
For more info, see Google's development guide and parameter reference for the protocol.
Note: I wrote this for a Drupal website for which we were implementing GUA tracking, but plan to isolate the (minimal) Drupal-specific code and add a Drupal-specific implementation that extends a generic GAMP base.