use only one layout for blog-posts and events, mark events as... well... events.

_layouts/event.html

----
-layout: default
----
-<div class="post">
-
-  <header class="post-header">
-    <h1 class="post-title">{{ page.title }}</h1>
-    <p class="post-meta">{{ page.date | date: "%b %-d, %Y" }}{% if page.author %} • {{ page.author }}{% endif %}{% if page.meta %} • {{ page.meta }}{% endif %}</p>
-		<p class="event-date">
-			Anfang: {{ page.eventstart | date: "%d.%m.%Y %H:%M" }}<br />
-			Ende: {{ page.eventend | date: "%d.%m.%Y %H:%M" }}<br />
-			Ort: {% if page.location %}{{ page.location }}{% else %}Free Software Lab{% endif %}
-			{% if page.organizer %}<br />Organisation: {{ page.organizer }}{% endif %}
-		</p>
-	</header>
-
-  <article class="post-content">
-    {{ content }}
-  </article>
-
-</div>

_layouts/post.html

@@ -4,8 +4,17 @@ layout: default
 <div class="post">
 
   <header class="post-header">
-    <h1 class="post-title">{{ page.title }}</h1>
+    <h1 class="post-title">{% if page.categories contains 'event' %}Termin: {% endif %}{{ page.title }}</h1>
     <p class="post-meta">{{ page.date | date: "%b %-d, %Y" }}{% if page.author %} • {{ page.author }}{% endif %}{% if page.meta %} • {{ page.meta }}{% endif %}</p>
+    {% if page.categories contains 'event' %}
+    <p class="event-date">
+      Anfang: {{ page.eventstart | date: "%d.%m.%Y %H:%M" }}<br />
+      Ende: {{ page.eventend | date: "%d.%m.%Y %H:%M" }}<br />
+      Ort: {% if page.location %}{{ page.location }}{% else %}Free Software Lab{% endif %}
+      {% if page.organizer %}<br />Organisation: {{ page.organizer }}{% endif %}
+    </p>
+    {% endif %}
+
   </header>
 
   <article class="post-content">

_posts/events/2015-05-15-chaos-cologne.markdown

 ---
-layout:     event
+layout:     post
 title:      "Chaos Cologne"
 date:       2015-04-28 17:20:36
 eventstart: 2015-05-15 20:00:00

index.html

@@ -35,7 +35,7 @@ layout: default
         <span class="post-meta">{{ post.date | date: "%b %-d, %Y" }}</span>
 
         <h2>
-          <a class="post-link" href="{{ post.url | prepend: site.baseurl }}">{{ post.title }}</a>
+          <a class="post-link" href="{{ post.url | prepend: site.baseurl }}">{% if post.categories contains 'event' %}Termin: {% endif %}{{ post.title }}</a>
         </h2>
       </li>
     {% endfor %}