A few fixes after more thorough review.

app/controllers/application.rb

@@ -173,7 +173,7 @@ class ApplicationController < ActionController::Base
     if show_from_date.nil?
       todo.show_from=nil
     else
-      todo.show_from = show_from_date.to_time < Time.now.utc ? nil : show_from_date
+      todo.show_from = show_from_date < Time.now.utc ? nil : show_from_date
     end
     
     saved = todo.save

app/models/preference.rb

@@ -21,7 +21,7 @@ class Preference < ActiveRecord::Base
   
   def parse_date(s)
     return nil if s.blank?
-    Date.strptime(s, date_format)
+    user.at_midnight(Date.strptime(s, date_format))
   end
   
 end

app/models/user.rb

@@ -71,7 +71,7 @@ class User < ActiveRecord::Base
            :conditions => [ 'state = ?', 'deferred' ],
            :order => 'show_from ASC, todos.created_at DESC' do
               def find_and_activate_ready
-                find(:all, :conditions => ['show_from <= ?', proxy_owner.date ]).collect { |t| t.activate! }
+                find(:all, :conditions => ['show_from <= ?', Time.now ]).collect { |t| t.activate! }
               end
            end
   has_many :completed_todos,

db/migrate/041_change_dates_to_datetimes.rb

@@ -4,17 +4,16 @@ class ChangeDatesToDatetimes < ActiveRecord::Migration
     change_column :todos, :due, :datetime
     change_column :recurring_todos, :start_from, :datetime
     change_column :recurring_todos, :end_date, :datetime
-    
+
     User.all(:include => [:todos, :recurring_todos]).each do |user|
-      zone = TimeZone[user.prefs.time_zone]
       user.todos.each do |todo|
-        todo.update_attribute(:show_from, user.at_midnight(todo.show_from)) unless d.nil?
-        todo.update_attribute(:due, user.at_midnight(todo.due)) unless d.nil?
+        todo.update_attribute(:show_from, user.at_midnight(todo.show_from)) unless todo.show_from.nil?
+        todo.update_attribute(:due, user.at_midnight(todo.due)) unless todo.due.nil?
       end
-      
+
       user.recurring_todos.each do |todo|
-        todo.update_attribute(:start_from, user.at_midnight(todo.start_from)) unless d.nil?
-        todo.update_attribute(:end_date, user.at_midnight(todo.end_date)) unless d.nil?
+        todo.update_attribute(:start_from, user.at_midnight(todo.start_from)) unless todo.start_from.nil?
+        todo.update_attribute(:end_date, user.at_midnight(todo.end_date)) unless todo.end_date.nil?
       end
     end
   end

spec/models/user_spec.rb

@@ -185,8 +185,9 @@ describe User do
     user.save!
     user.create_preference
     user.preference.update_attribute('time_zone', 'Pacific Time (US & Canada)')
+#    Time.zone = 'Pacific Time (US & Canada)'
     Time.stub!(:now).and_return(Time.new.end_of_day - 20.minutes)
-    todo = user.todos.build(:description => 'test task', :context => context, :show_from => user.date + 1)
+    todo = user.todos.build(:description => 'test task', :context => context, :show_from => user.date + 1.days)
     todo.save!
 
     user.deferred_todos.find_and_activate_ready

test/unit/preference_test.rb

@@ -20,7 +20,7 @@ class PreferenceTest < Test::Rails::TestCase
   end
   
   def test_parse_date
-    assert_equal Date.new(2007, 5, 20).to_s, @admin_user.preference.parse_date('20/5/2007').to_s
+    assert_equal @admin_user.at_midnight(Date.new(2007, 5, 20)).to_s, @admin_user.preference.parse_date('20/5/2007').to_s
   end
   
   def test_parse_date_returns_nil_if_string_is_empty

test/unit/user_test.rb

@@ -235,7 +235,7 @@ class UserTest < Test::Rails::TestCase
 
   def test_find_and_activate_deferred_todos_that_are_ready
     assert_equal 1, @admin_user.deferred_todos.count
-    @admin_user.deferred_todos[0].show_from = @admin_user.date
+    @admin_user.deferred_todos[0].show_from = Time.now - 5.seconds
     @admin_user.deferred_todos[0].save
     @admin_user.deferred_todos.reload
     @admin_user.deferred_todos.find_and_activate_ready