diff --git a/rails/map-mash/app/models/mash_tournament.rb b/rails/map-mash/app/models/mash_tournament.rb
index 6b6763c..03291be 100644
--- a/rails/map-mash/app/models/mash_tournament.rb
+++ b/rails/map-mash/app/models/mash_tournament.rb
@@ -16,105 +16,4 @@ class MashTournament < ActiveRecord::Base
         :conditions => {:number => number}
     )
   end
-
-  def valid_number_of_contenders?(n_contenders)
-    [8, 16, 32, 64, 128].include?(n_contenders)
-  end
-
-  def create_rounds_for_contenders(n_contenders)
-    if not valid_number_of_contenders?(n_contenders)
-      raise StandardError.new(
-        "The number of contenders must be 8, 16, 32, 64, or 128!  " +
-        "Got '#{n_contenders}'"
-      )
-    end
-
-    round = 1
-
-    while n_contenders > 1
-      create_round(round, n_contenders)
-      n_contenders = n_contenders / 2
-      round += 1
-    end
-
-    self.total_rounds = round - 1
-  end
-
-  def fill_in_next_round
-    self.rounds.sort{ |a,b| a.number <=> b.number}.each do |round|
-      if not round.done?
-        return assign_maps_for_round(round)
-      end
-    end
-  end
-
-  private
-  def create_round(round_number, n_contenders)
-    round = MashTournamentRound.new(
-      :mash_tournament_id => self.id,
-      :number => round_number,
-      :mash_count => n_contenders / 2
-    )
-    round.save!
-
-    n_contenders.times do
-      Mash.new(
-        :mash_tournament_id => self.id,
-        :mash_tournament_round_id => round.id
-      ).save!
-    end
-  end
-
-  def assign_maps_for_round(round)
-    if round.number == 1
-      return assign_maps_for_round_one(round)
-    end
-
-    previous = MashTournamentRound.find_by_mash_tournament_id_and_number(
-                  self.id, round.number - 1
-                )
-    previous_winners = previous.mashes.collect(&:winner_id)
-    pool = Map.all(
-      :order => 'RANDOM()',
-      :conditions => ['id in ?', previous_winners]
-    )
-
-    filled_in = []
-
-    round.mashes.each do |mash|
-      mash.map_a = pool.pop.id
-      mash.map_b = pool.pop.id
-      mash.save!
-
-      filled_in << mash
-    end
-
-    filled_in
-  end
-
-  def assign_maps_for_round_one(round)
-    pool = Map.all(
-      :order => 'RANDOM()',
-      :limit => round.mash_count * 2
-    )
-
-    logger.info("Populating mashes from pool: #{pool.inspect}")
-
-    filled_in = []
-
-    round.mashes.each do |mash|
-      map_a = pool.pop
-      map_b = pool.pop
-      logger.info("Assigning `map_a` from #{map_a.inspect}, " +
-                  "`map_b` from #{map_b.inspect} to mash #{mash.inspect}")
-
-      mash.map_a = map_a
-      mash.map_b = map_b
-      mash.save!
-
-      filled_in << mash
-    end
-
-    filled_in
-  end
 end
diff --git a/rails/map-mash/lib/mash_tournament_builder.rb b/rails/map-mash/lib/mash_tournament_builder.rb
new file mode 100644
index 0000000..7d5aa78
--- /dev/null
+++ b/rails/map-mash/lib/mash_tournament_builder.rb
@@ -0,0 +1,113 @@
+class MashTournamentBuilder
+  attr_accessor :tournament, :tournament_model, :round_model
+  attr_accessor :map_model, :mash_model
+
+  def initialize(tournament, tournament_model, round_model, map_model, mash_model)
+    @tournament = tournament
+    @tournament_model = tournament_model
+    @round_model = round_model
+    @map_model = map_model
+    @mash_model = mash_model
+  end
+
+  def valid_number_of_contenders?(n_contenders)
+    [8, 16, 32, 64, 128].include?(n_contenders)
+  end
+
+  def create_rounds_for_contenders(n_contenders)
+    if not valid_number_of_contenders?(n_contenders)
+      raise StandardError.new(
+        "The number of contenders must be 8, 16, 32, 64, or 128!  " +
+        "Got '#{n_contenders}'"
+      )
+    end
+
+    round = 1
+
+    while n_contenders > 1
+      create_round(round, n_contenders)
+      n_contenders = n_contenders / 2
+      round += 1
+    end
+
+    @tournament.total_rounds = round - 1
+  end
+
+  def fill_in_next_round
+    @tournament.rounds.sort{ |a,b| a.number <=> b.number}.each do |round|
+      if not round.done?
+        return assign_maps_for_round(round)
+      end
+    end
+  end
+
+  private
+  def create_round(round_number, n_contenders)
+    round = @round_model.new(
+      :mash_tournament_id => @tournament.id,
+      :number => round_number,
+      :mash_count => n_contenders / 2
+    )
+    round.save!
+
+    n_contenders.times do
+      @mash_model.new(
+        :mash_tournament_id => @tournament.id,
+        :mash_tournament_round_id => round.id
+      ).save!
+    end
+  end
+
+  def assign_maps_for_round(round)
+    if round.number == 1
+      return assign_maps_for_round_one(round)
+    end
+
+    previous = @round_model.find_by_mash_tournament_id_and_number(
+                  @tournament.id, round.number - 1
+                )
+    previous_winners = previous.mashes.collect(&:winner_id)
+    pool = @map_model.all(
+      :order => 'RANDOM()',
+      :conditions => ['id in ?', previous_winners]
+    )
+
+    filled_in = []
+
+    round.mashes.each do |mash|
+      mash.map_a = pool.pop.id
+      mash.map_b = pool.pop.id
+      mash.save!
+
+      filled_in << mash
+    end
+
+    filled_in
+  end
+
+  def assign_maps_for_round_one(round)
+    pool = @map_model.all(
+      :order => 'RANDOM()',
+      :limit => round.mash_count * 2
+    )
+
+    logger.info("Populating mashes from pool: #{pool.inspect}")
+
+    filled_in = []
+
+    round.mashes.each do |mash|
+      map_a = pool.pop
+      map_b = pool.pop
+      logger.info("Assigning `map_a` from #{map_a.inspect}, " +
+                  "`map_b` from #{map_b.inspect} to mash #{mash.inspect}")
+
+      mash.map_a = map_a
+      mash.map_b = map_b
+      mash.save!
+
+      filled_in << mash
+    end
+
+    filled_in
+  end
+end
diff --git a/rails/map-mash/spec/lib/mash_tournament_builder_spec.rb b/rails/map-mash/spec/lib/mash_tournament_builder_spec.rb
new file mode 100644
index 0000000..63d1fa3
--- /dev/null
+++ b/rails/map-mash/spec/lib/mash_tournament_builder_spec.rb
@@ -0,0 +1,64 @@
+require 'spec_helper'
+
+describe MashTournamentBuilder do
+  let(:subject) do
+    MashTournamentBuilder.new(
+      MashTournament.make(:requester => Requester.make),
+      MashTournament, MashTournamentRound, Map, Mash
+    )
+  end
+
+  let(:mock_subject) do
+    @tournament = mock(Object)
+    @tournament_model = mock(Object)
+    @round_model = mock(Object)
+    @map_model = mock(Object)
+    @mash_model = mock(Object)
+
+    MashTournamentBuilder.new(
+      @tournament, @tournament_model,
+      @round_model, @map_model, @mash_model
+    )
+  end
+
+  context 'creating rounds' do
+    it 'should reject invalid numbers of contenders' do
+      [11, 24, 40].each do |n|
+        expect do
+          subject.create_rounds_for_contenders(n)
+        end.to raise_error
+      end
+    end
+
+    before(:all) do
+      subject.map_model.destroy_all
+      40.times do
+        subject.map_model.make.save
+      end
+    end
+
+    [[8, 3], [16, 4], [32, 5]].each do |n_contenders,n_rounds|
+      context "for #{n_contenders} total contenders" do
+        it "should create #{n_rounds} rounds" do
+          subject.create_rounds_for_contenders(n_contenders)
+          subject.tournament.total_rounds.should == n_rounds
+        end
+      end
+    end
+  end
+
+  context 'filling in rounds' do
+    before(:each) do
+      subject.id.should_not be_nil
+      subject.create_rounds_for_contenders(8)
+    end
+
+    xit 'should fill in every map for every mash in a given round' do
+      subject.fill_in_next_round
+      subject.round(1).mashes.each do |mash|
+        mash.map_a.should_not be_nil
+        mash.map_b.should_not be_nil
+      end
+    end
+  end
+end
diff --git a/rails/map-mash/spec/models/mash_tournament_spec.rb b/rails/map-mash/spec/models/mash_tournament_spec.rb
index c28d154..734b760 100644
--- a/rails/map-mash/spec/models/mash_tournament_spec.rb
+++ b/rails/map-mash/spec/models/mash_tournament_spec.rb
@@ -5,56 +5,7 @@ describe MashTournament do
     @valid_attributes = {:requester_id => 1}
   end
 
-  before(:each) do
-    @requester = Requester.make
-    @requester.save!
-    subject.requester_id = @requester.id
-    subject.save!
-    subject.reload
-  end
-
   it "should create a new instance given valid attributes" do
     MashTournament.create!(@valid_attributes)
   end
-
-  context 'creating rounds' do
-    it 'should reject invalid numbers of contenders' do
-      [11, 24, 40].each do |n|
-        expect do
-          subject.create_rounds_for_contenders(n)
-        end.to raise_error
-      end
-    end
-
-    before(:all) do
-      Map.destroy_all
-      40.times do
-        Map.make.save
-      end
-    end
-
-    [[8, 3], [16, 4], [32, 5]].each do |n_contenders,n_rounds|
-      context "for #{n_contenders} total contenders" do
-        it "should create #{n_rounds} rounds" do
-          subject.create_rounds_for_contenders(n_contenders)
-          subject.total_rounds.should == n_rounds
-        end
-      end
-    end
-  end
-
-  context 'filling in rounds' do
-    before(:each) do
-      subject.id.should_not be_nil
-      subject.create_rounds_for_contenders(8)
-    end
-
-    xit 'should fill in every map for every mash in a given round' do
-      subject.fill_in_next_round
-      subject.round(1).mashes.each do |mash|
-        mash.map_a.should_not be_nil
-        mash.map_b.should_not be_nil
-      end
-    end
-  end
 end