diff --git a/Gemfile b/Gemfile
index 6a26b71f..a959447a 100644
--- a/Gemfile
+++ b/Gemfile
@@ -12,6 +12,4 @@ gem 't'
 gem 'nokogiri'
 gem 'feedzirra'
 gem 'ri_cal'
-gem 'tzinfo'
-gem 'tzinfo-data'
 
diff --git a/Gemfile.lock b/Gemfile.lock
index 08038289..0ecd68d1 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -123,9 +123,6 @@ GEM
       faraday (~> 0.8, < 0.10)
       multi_json (~> 1.0)
       simple_oauth (~> 0.2)
-    tzinfo (1.0.1)
-    tzinfo-data (1.2013.4)
-      tzinfo (>= 1.0.0)
     yajl-ruby (1.1.0)
 
 PLATFORMS
@@ -143,5 +140,3 @@ DEPENDENCIES
   sass
   systemu
   t
-  tzinfo
-  tzinfo-data
diff --git a/content/events/200705/index.md b/content/events/200705/index.md
index 31fd926e..0b7ac1a9 100644
--- a/content/events/200705/index.md
+++ b/content/events/200705/index.md
@@ -1,6 +1,6 @@
 ---
 kind: event
-startdate: 2007-05-10T19:30:00
+startdate: 2007-05-10T19:30:00Z
 duration: 2h
 title: "DNS & Domainvergabe - wie geht das eigentlich"
 speakers:
diff --git a/content/events/201301-fahrrad-illumination/index.md b/content/events/201301-fahrrad-illumination/index.md
index dc539120..238940bf 100644
--- a/content/events/201301-fahrrad-illumination/index.md
+++ b/content/events/201301-fahrrad-illumination/index.md
@@ -1,6 +1,6 @@
 ---
 kind: event
-startdate: 2013-01-10T19:30:00
+startdate: 2013-01-10T19:30:00Z
 duration: 2h
 title: "Fahrrad-Illumination: heller als die Polizei erlaubt"
 speakers:
diff --git a/content/events/201302-sammeln-von-grossrechnern/index.md b/content/events/201302-sammeln-von-grossrechnern/index.md
index db6d2d44..762c6cb0 100644
--- a/content/events/201302-sammeln-von-grossrechnern/index.md
+++ b/content/events/201302-sammeln-von-grossrechnern/index.md
@@ -1,6 +1,6 @@
 ---
 kind: event
-startdate: 2013-02-14T19:30:00
+startdate: 2013-02-14T19:30:00Z
 duration: 2h
 title: "Über die besonderen Anforderungen beim Sammeln von historischen Großrechnern"
 speakers:
diff --git a/content/events/201303-pretty-easy-privacy-chat/index.md b/content/events/201303-pretty-easy-privacy-chat/index.md
index f59a2073..16857966 100644
--- a/content/events/201303-pretty-easy-privacy-chat/index.md
+++ b/content/events/201303-pretty-easy-privacy-chat/index.md
@@ -1,6 +1,6 @@
 ---
 kind: event
-startdate: 2013-03-14T19:30:00
+startdate: 2013-03-14T19:30:00Z
 duration: 2h
 title: "Pretty Easy Privacy - Chat"
 speakers:
diff --git a/content/events/201304-bericht-aus-der-internet-enquete-kommission/index.md b/content/events/201304-bericht-aus-der-internet-enquete-kommission/index.md
index 30cfd64b..d50645fe 100644
--- a/content/events/201304-bericht-aus-der-internet-enquete-kommission/index.md
+++ b/content/events/201304-bericht-aus-der-internet-enquete-kommission/index.md
@@ -1,6 +1,6 @@
 ---
 kind: event
-startdate: 2013-04-11T19:30:00
+startdate: 2013-04-11T19:30:00Z
 duration: 2h
 title: "Bericht aus der Internet-Enquête-Kommision"
 speakers:
diff --git a/content/events/201305-frauen-in-der-informatik/index.md b/content/events/201305-frauen-in-der-informatik/index.md
index 4ebf39fa..ba180dd1 100644
--- a/content/events/201305-frauen-in-der-informatik/index.md
+++ b/content/events/201305-frauen-in-der-informatik/index.md
@@ -1,6 +1,6 @@
 ---
 kind: event
-startdate: 2013-05-16T19:30:00
+startdate: 2013-05-16T19:30:00Z
 duration: 2h
 title: "Frauen in der Informatik und ihre Arbeitsbedingungen"
 speakers:
diff --git a/content/events/201307-der-facebook-hack/index.md b/content/events/201307-der-facebook-hack/index.md
index 8d745135..91bd6a51 100644
--- a/content/events/201307-der-facebook-hack/index.md
+++ b/content/events/201307-der-facebook-hack/index.md
@@ -1,6 +1,6 @@
 ---
 kind: event
-startdate: 2013-07-11T19:30:00
+startdate: 2013-07-11T19:30:00Z
 duration: 2h
 title: "Der Facebook-Hack - Erlebnisse bei strafrechtliche Ermittlungen in Sozialen Netzwerken oder Festplatten zu beschlagnahmen"
 speakers:
diff --git a/content/events/201308-datenschutz-in-unternehmen/index.md b/content/events/201308-datenschutz-in-unternehmen/index.md
index cb97e8f3..aff87798 100644
--- a/content/events/201308-datenschutz-in-unternehmen/index.md
+++ b/content/events/201308-datenschutz-in-unternehmen/index.md
@@ -1,6 +1,6 @@
 ---
 kind: event
-startdate: 2013-08-15T19:30:00
+startdate: 2013-08-15T19:30:00Z
 duration: 2h
 title: "Datenschutz in Unternehmen und Organisationen - Bewertung in unterschiedlichen Kontexten"
 speakers:
diff --git a/content/events/201309-prism-tempora-und-co/index.md b/content/events/201309-prism-tempora-und-co/index.md
index d73f5548..79fad567 100644
--- a/content/events/201309-prism-tempora-und-co/index.md
+++ b/content/events/201309-prism-tempora-und-co/index.md
@@ -1,6 +1,6 @@
 ---
 kind: event
-startdate: 2013-09-12T19:30:00
+startdate: 2013-09-12T19:30:00Z
 duration: 2h
 title: "Prism, Tempora und Co. - Wie wir überwacht werden und wie wir uns verteidigen können"
 speakers:
diff --git a/content/events/201311-digitale-langzeitarchivierung/index.md b/content/events/201311-digitale-langzeitarchivierung/index.md
index 56728b41..e1d3bb67 100644
--- a/content/events/201311-digitale-langzeitarchivierung/index.md
+++ b/content/events/201311-digitale-langzeitarchivierung/index.md
@@ -1,6 +1,6 @@
 ---
 kind: event
-startdate: 2013-11-14T19:30:00
+startdate: 2013-11-14T19:30:00Z
 duration: 2h
 title: "Wenn Schiller die Räuber mit Wordstar geschrieben hätte - digitale Langzeitarchivierung am Deutschen Literaturarchiv Marbach"
 speakers:
diff --git a/lib/eventhelpers.rb b/lib/eventhelpers.rb
index 7fa1fa2c..22730bc0 100644
--- a/lib/eventhelpers.rb
+++ b/lib/eventhelpers.rb
@@ -41,16 +41,24 @@ def calculate_to_dates()
   end
 end
 
+def conv_tz(t)
+  if (t.utc?)
+    Time.local(t.year, t.month, t.day, t.hour, t.min, t.sec)
+  else
+    t
+  end
+end
+
 def fix_timezones()
   items.each do |e|
     if e[:created_at] && e[:created_at].instance_of?(Time)
-      e[:created_at] = e[:created_at].utc
+      e[:created_at] = conv_tz(e[:created_at])
     end
     if e[:startdate] && e[:startdate].instance_of?(Time)
-      e[:startdate] = e[:startdate].utc
+      e[:startdate] = conv_tz(e[:startdate])
     end
     if e[:enddate] && e[:enddate].instance_of?(Time)
-      e[:enddate] = e[:enddate].utc
+      e[:enddate] = conv_tz(e[:enddate])
     end
   end
 end
diff --git a/scripts/generate-stammtisch.rb b/scripts/generate-stammtisch.rb
index b23593dd..a09e05ac 100755
--- a/scripts/generate-stammtisch.rb
+++ b/scripts/generate-stammtisch.rb
@@ -2,14 +2,10 @@
 # encoding: utf-8
 
 require 'date'
-require 'tzinfo'
 require 'yaml'
 
 
 def event(day, dayoffset, location)
-  #startDate = Time.new(day.year, day.month, day.day + dayoffset, 18, 0, 0, "+02:00")
-  #tz = TZInfo::Timezone.get('Europe/Berlin')
-  #startDate = tz.local_to_utc(Time.local(day.year, day.month, day.day + dayoffset, 18, 0, 0))
   startDate = Time.local(day.year, day.month, day.day + dayoffset, 18, 0, 0)
   {
     'startdate' => startDate,