countdown-by-category.php

<?php
add_shortcode( 'countdown_by_category', 'countdown_by_category_build' );
/**
 * A wrapper shortcode for the [tribe_event_countdown] shorcode to allow
 * displaying countdown by event category
 */
function countdown_by_category_build( $atts, $content = null ) {
	extract( shortcode_atts( array(
		'category' 	=> ''
	), $atts, 'countdown_by_category' ) );
	
	ob_start();
	
	$args = array(
		'post_type' 	=> 'tribe_events',
		'tax_query' 	=> array(
			array(
				'taxonomy' 	=> 'tribe_events_cat',
				'field' 	=> 'slug',
				'terms' 	=> $category
			)
		),
		'posts_per_page' 	=> 1
	);
	
	$event = get_posts( $args );
	
	echo do_shortcode('[tribe_event_countdown id='. $event->ID .']');
	
	$countdown = ob_get_clean();
	
	return $countdown;
}