A demo for Gydo. Based on this: http://mikejolley.com/2012/12/using-the-new-wordpress-3-5-media-uploader-in-plugins/

Gydo.js

var file_frame;

// "mca_tray_button" is the ID of my button that opens the Media window
jQuery('#mca_tray_button').live('click', function( event ){

  event.preventDefault();

	if ( file_frame ) {
		file_frame.open();
		return;
	}

	file_frame = wp.media.frames.file_frame = wp.media({
		title: jQuery( this ).data( 'uploader_title' ),
		button: {
			text: jQuery( this ).data( 'uploader_button_text' ),
		},
		multiple: false  
	});

	file_frame.on( 'select', function() {

		attachment = file_frame.state().get('selection').first().toJSON();

		// "mca_features_tray" is the ID of my text field that will receive the image
		// I'm getting the ID rather than the URL:

		jQuery("#mca_features_tray").val(attachment.id);

		// but you could get the URL instead by doing something like this:
		jQuery("#mca_features_tray").val(attachment.sizes.thumbnail.url);

		// and you can change "thumbnail" to get other image sizes

	});

	file_frame.open();

});