diff --git a/Rules b/Rules
index dd52ef74..72bda818 100644
--- a/Rules
+++ b/Rules
@@ -3,6 +3,7 @@
 preprocess do
   expand_event_list("/_data/chaosevents/")
   expand_event_list("/_data/stammtisch/", "CCCS Stammtisch")
+  calculate_to_dates
   merge_location_data
   generate_event_pages
   generate_activity_pages
diff --git a/content/_data/chaosevents.yaml b/content/_data/chaosevents.yaml
index f3ba05ab..5d2b1825 100644
--- a/content/_data/chaosevents.yaml
+++ b/content/_data/chaosevents.yaml
@@ -3,7 +3,7 @@ events:
   -
     #kind: event
     startdate: 2013-09-06
-    duration: 2d
+    duration: 3d
     title: "MRMCD2013 - Security Advice"
     url: http://mrmcd.net/
     location:
@@ -15,7 +15,7 @@ events:
     #public: true
   -
     startdate: 2013-12-27
-    duration: 3d
+    duration: 4d
     title: "30C3"
     url: https://events.ccc.de/
     location:
diff --git a/content/sidebar.html b/content/sidebar.html
index 212d4b8d..ed26171f 100644
--- a/content/sidebar.html
+++ b/content/sidebar.html
@@ -9,7 +9,15 @@ if (upcomingEvents.size>0)
 <ul>
   <% upcomingEvents[0..9].each do |e| %>
   <li>
-    <%= e[:startdate].strftime("%d.%m.") %>
+    <% if e[:startdate].instance_of?(Date) %>
+    <% if e[:startdate]<e[:enddate] %>
+    <%= e[:startdate].strftime("%d.%m.") %> - <%= e[:enddate].strftime("%d.%m.") %>:
+    <% else %>
+    <%= e[:startdate].strftime("%d.%m.") %>:
+    <% end %>
+    <% else %>
+    <%= e[:startdate].strftime("%d.%m., %H:%M") %>:
+    <% end %>
     <% if e[:url] %><a href="<%= e[:url] %>"><%= e[:title] %></a><% else %><%= e[:title] %><% end %>
     </li>
   <% end %>
diff --git a/lib/eventhelpers.rb b/lib/eventhelpers.rb
index 68a81eb7..38af752a 100644
--- a/lib/eventhelpers.rb
+++ b/lib/eventhelpers.rb
@@ -24,3 +24,20 @@ def get_public_events()
   items.select { |i| (i[:kind]=='event') && i[:public] }
 end
 
+def calculate_to_dates()
+  items.select { |i| (i[:kind]=='event') && i[:duration] }.each do |e|
+    if e[:startdate].instance_of?(Date)
+      if e[:duration] =~ /(\d+)d/
+        e[:enddate] = e[:startdate] + ($1.to_i - 1)
+      end
+    else
+      if e[:duration] =~ /(\d+)h/
+        e[:enddate] = e[:startdate] + 60*60*$1.to_i
+      end
+      if e[:duration] =~ /(\d+)m/
+        e[:enddate] = e[:startdate] + 60*$1.to_i
+      end
+    end
+  end
+end
+