Step 1:

add_action( 'init', 'videogames', 0 );
function videogames() {
	register_taxonomy( 'xbox360', 'post', array( 'hierarchical' => false, 'label' => 'Xbox 360', 'query_var' => true, 'rewrite' => true ) );
	register_taxonomy( 'playstation3', 'post', array( 'hierarchical' => false, 'label' => 'PlayStation 3', 'query_var' => true, 'rewrite' => true ) );
	register_taxonomy( 'wii', 'post', array( 'hierarchical' => false, 'label' => 'Wii', 'query_var' => true, 'rewrite' => true ) );
}

Step 2:

<?php echo get_the_term_list( $post->ID, 'xbox360', 'Xbox 360 games: ', ', ', '' ); ?>

Step 3:

<?php wp_tag_cloud( array( 'taxonomy' => 'xbox360', 'number' => 25 ) ); ?>

Step 4:

<?php query_posts( array( 'xbox360' => 'the-super-game', 'showposts' => 25 ) ); ?>