Vimeo tracking object, assuming you're using https://github.com/vimeo/player-api/tree/master/javascript

vimeo-tracking.js

//simply use Vimeo.init(); to find the videos and bind the events
var Vimeo = {
	// we can add more events when we need to, e.g. onPause
	events: {
		// when videos are ready, we can attach our events
		ready: function( player_id ) {
			$f(player_id).addEvent( 'play', Vimeo.events.onPlay );
		},

		//when the play button is clicked
		onPlay: function( player_id ) {
			//clean up the string for track event by removing the hyphens
			var trackEvString = player_id.replace( /-/g, ' ' );
					
			//track event (GA)
			if(_gaq) _gaq.push(['_trackEvent', 'Video', 'play', trackEvString]);
		}
	},

	// collects the videos on the page and binds events
	init: function() {
		var 	i = 0,
			videos = $( '.vimeo-video' ),
			length = videos.length,
			player = null;
    
		for ( i; i < length; i++ ) {
			player = videos[i];
			$f( player ).addEvent( 'ready', Vimeo.events.ready );
		}
	}
};