diff --git a/Gemfile.lock b/Gemfile.lock
index 5f01b25..314fa4a 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -3,6 +3,7 @@ PATH
   specs:
     birthdaze (0.0.1)
       carddav
+      icalendar
       thor
 
 GEM
@@ -13,6 +14,9 @@ GEM
       nokogiri
       vcardigan
     curb (1.0.5)
+    icalendar (2.10.1)
+      ice_cube (~> 0.16)
+    ice_cube (0.16.4)
     nokogiri (1.16.2-x86_64-linux)
       racc (~> 1.4)
     racc (1.7.3)
diff --git a/birthdaze.gemspec b/birthdaze.gemspec
index 33c85d7..c55d493 100644
--- a/birthdaze.gemspec
+++ b/birthdaze.gemspec
@@ -8,7 +8,8 @@ Gem::Specification.new do |s|
   s.files       = Dir["lib/**/*", "MIT-LICENSE", "README.md"]
   s.license     = "MIT"
   s.executables << "birthdaze"
-  s.add_dependency "thor"
   s.add_dependency "carddav"
+  s.add_dependency "icalendar"
+  s.add_dependency "thor"
 end
 
diff --git a/lib/birthdaze.rb b/lib/birthdaze.rb
index 6c6ee2e..96d46f7 100644
--- a/lib/birthdaze.rb
+++ b/lib/birthdaze.rb
@@ -1,4 +1,5 @@
 require "carddav"
+require "icalendar"
 require "thor"
 require "yaml"
 
@@ -6,7 +7,20 @@ class Birthdaze < Thor
   desc "generate", "Generate calendars"
   def generate
     puts "Generate calendars"
-    birthdays
+    puts calendar.inspect
+  end
+
+  desc "list", "List birthdays"
+  def list
+    display = birthdays.map do |name, birthday|
+      {
+        name: name,
+        month: month_of(start_date(birthday)),
+        day: day_of(start_date(birthday)),
+      }
+    end
+    display.sort! { |a, b| a[:month] == b[:month] ? a[:day] <=> b[:day] : a[:month] <=> b[:month] }
+    display.each { |d| puts "🎂 #{d[:month]}/#{d[:day]} - #{d[:name]}" }
   end
 
   private
@@ -25,14 +39,65 @@ class Birthdaze < Thor
   end
 
   def birthdays
-    birthdays = []
+    return @birthdays if defined? @birthdays
+
+    @birthdays = []
     client.cards.each do |card|
       card = card.parsed.to_s
       birthday = birthday_regex.match(card)[1] if birthday_regex.match?(card)
       name = name_regex.match(card)[1] if name_regex.match?(card)
-      birthdays << [ name, birthday ] if name && birthday
+      @birthdays << [ name, birthday ] if name && birthday
     end
-    birthdays
+    @birthdays
+  end
+
+  def calendar
+    return @calendar if defined? @calendar
+
+    @calendar = Icalendar::Calendar.new
+    birthdays.each do |name, birthday|
+      @calendar.event do |event|
+        puts name
+        event.dtstart = Icalendar::Values::Date.new(start_date(birthday))
+        event.dtend = Icalendar::Values::Date.new(end_date(birthday))
+        event.summary = summary(name, birthday)
+      end
+    end
+    @calendar.publish
+  end
+
+  # Takes a birthday string, with or without a year, and returns a start date
+  def start_date(birthday)
+    year = Date.today.year
+    birthday = birthday.tr("-", "")
+    birthday = birthday.gsub("1604", "") if birthday.start_with?("1604")
+    if birthday.length < 8 # No year specified
+      "#{year}#{birthday[0..3]}"
+    else
+      "#{year}#{birthday[4..7]}"
+    end
+  end
+
+  def end_date(birthday)
+    year = Date.today.year
+    birthday = birthday.tr("-", "")
+    birthday = birthday.gsub("1604", "") if birthday.start_with?("1604")
+    if birthday.length < 8 # No year specified
+      "#{year}#{birthday[0..1]}#{birthday[2..3].to_i + 1}"
+    else
+      "#{year}#{birthday[4..5]}#{birthday[6..7].to_i + 1}"
+    end
+  end
+
+  def summary(name, birthday)
+    return "#{name}’s birthday" if birthday.start_with?("-") || birthday.start_with?("1604")
+
+    birth_year = birthday[0..3].to_i
+    age = Date.today.year - birth_year + 1
+    "🎂 #{name}’s #{age} birthday"
+  end
+
+  def set_reminders
   end
 
   def birthday_regex
@@ -43,4 +108,12 @@ class Birthdaze < Thor
   def name_regex
     /FN.*:(.*)/
   end
+
+  def month_of(date)
+    date.length < 8 ? date[0..1] : date[4..5]
+  end
+
+  def day_of(date)
+    date.length < 8 ? date[2..3] : date[6..7]
+  end
 end