Randomly display activity posts on home page with buddypress

And why not using simple wordpress code, changing args ?

$args = array(
        'post_type'      => 'post',
        'orderby'        => 'rand',
        'posts_per_page' => '1',
    );
    $my_query = new WP_Query( $args );
    if ( $my_query->have_posts() ) {
        while ( $my_query->have_posts() ) {
            $my_query->the_post();

            /* do your post output here */

        } // end while
    } // end if