Graham mans_bx Ok you would need to adapt this to fit your own custom blog twig and post list markup it is only to prove the concept
it does not give the entire post but it will give a random post list entry
This is in normal xtgem blog markup where the standard xtblog.twig has been renamed blog.twig

{% if data.translations.t_no_entries_found == 'random' and view == 'entries_list'%} {% set entry=data.entries[random(data.entries|length-1)]%} <div> <a class="xt_blog_title_link" href="{{ entry.url }}"> <span class="xt_heading">{{ entry.title }}{% if data.entry_list_show_time %} <span class="xt_blog_entry_time">{{entry.created}}</span>{% endif %}</span> {% if entry.comments_count %} <span class="xt_blog_comments_number">( {{ entry.comments_count }} )</span> {% endif %} </a> {% if data.display_type != 'header' and entry.content %} <span class="xt_description">{{ entry.content|raw }}</span> {% endif %} </div> {%else%} {%include 'blog.twig'%} {%endif%}

You then need a blog function with entries_per_page="0" and t_no_entries_found="random"
Remember that this can mess up the blog block id if you have other blog functions on the page so you may also need to allow for that